SOLID-STATE REFRIGERATION APPARATUS

Abstract

A solid-state refrigeration apparatus includes a plurality of solid refrigerators, a heating medium circuit with the plurality of solid refrigerators connected, and a conveying mechanism to convey a heating medium in the heating medium circuit. Each of the solid refrigerators includes a solid refrigerant substance having a caloric effect on an external energy and an induction section to cause the solid refrigerant substance to produce the caloric effect. The heating medium circuit includes first and second channels in which the solid refrigerators are connected in series and through which the heating medium is supplied to first and second heat exchange sections. At least one bypass mechanism is connected to the first and/or second channel. The bypass mechanism switches between an action of making the heating medium flow through the solid refrigerator and an action of making the heating medium bypass the solid refrigerator.

Description

BACKGROUND

Technical Field

The present disclosure relates to a solid-state refrigeration apparatus.

Background Art

Japanese Unexamined Patent Publication No. 2012-255642 discloses a magnetic refrigeration apparatus having a plurality of magnetic refrigerators connected in series in a main flow path through which a heating medium is conveyed. A bypass channel that bypasses one of the magnetic refrigerators is connected to the main flow path. A valve is provided in the bypass channel. In the magnetic refrigeration apparatus, a conveying mechanism allows the heating medium to flow back and forth in the main flow path. When the valve closes the bypass channel, the heating medium sequentially flows through the plurality of magnetic refrigerators. When the valve opens the bypass channel, the heating medium flows through one of the magnetic refrigerators and bypasses the other magnetic refrigerator.

SUMMARY

A first aspect is directed to a solid-state refrigeration apparatus that includes a plurality of solid refrigerators, a heating medium circuit with the plurality of solid refrigerators connected thereto, and a conveying mechanism configured to convey a heating medium in the heating medium circuit. The plurality of solid refrigerators each include a solid refrigerant substance configured to have a caloric effect on an external energy and an induction section configured to cause the solid refrigerant substance to produce the caloric effect. The heating medium circuit includes first and second channels in which the solid refrigerators are connected in series and through which the heating medium conveyed by the conveying mechanism is supplied to first and second heat exchange sections. At least one bypass mechanism is connected to at least one of the first channel and the second channel. The at least one bypass mechanism is configured to switch between an action of making the heating medium flow through the solid refrigerator and an action of making the heating medium bypass the solid refrigerator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a piping system diagram of a magnetic refrigeration apparatus according to a first embodiment.

FIG. 2 is a block diagram illustrating relationship between a controller and other components of the magnetic refrigeration apparatus of the first embodiment.

FIG. 3 shows graphs of characteristics of magnetic working substances of a first magnetic refrigerator and a second magnetic refrigerator according to the first embodiment.

FIG. 4 shows a graph of characteristics of adjacent magnetic working substances according to the first embodiment.

FIG. 5 is a diagram corresponding to FIG. 1 illustrating the flow of a heating medium in a normal heating action according to the first embodiment.

FIG. 6 is a diagram corresponding to FIG. 1 illustrating the flow of a heating medium in a normal cooling action according to the first embodiment.

FIG. 7 is a diagram corresponding to FIG. 1 illustrating the flow of a heating medium in a first bypass heating action according to the first embodiment.

FIG. 8 is a diagram corresponding to FIG. 1 illustrating the flow of a heating medium in a second bypass heating action according to the first embodiment.

FIG. 9 is a diagram corresponding to FIG. 1 illustrating the flow of a heating medium in a first bypass cooling action according to the first embodiment.

FIG. 10 is a diagram corresponding to FIG. 1 illustrating the flow of a heating medium in a second bypass cooling action according to the first embodiment.

FIG. 11 show graphs of characteristics of magnetic working substances of a first magnetic refrigerator and a second magnetic refrigerator according to a second embodiment.

FIG. 12 is a piping system diagram of a magnetic refrigeration apparatus according to a third embodiment.

FIG. 13 is a piping system diagram of a magnetic refrigeration apparatus according to a first variation of the third embodiment.

FIG. 14 is a piping system diagram of a magnetic refrigeration apparatus according to a second variation of the third embodiment.

FIG. 15 is a piping system diagram of a magnetic refrigeration apparatus according to a fourth embodiment.

FIG. 16 is a diagram corresponding to FIG. 15, illustrating the flow of a heating medium in a first action according to the fourth embodiment.

FIG. 17 is a diagram corresponding to FIG. 15, illustrating the flow of a heating medium in a second action according to the fourth embodiment.

FIG. 18 is a diagram corresponding to FIG. 15, illustrating the flow of a heating medium in a third action according to the fourth embodiment.

FIG. 19 is a diagram corresponding to FIG. 15, illustrating the flow of a heating medium in a fourth action according to the fourth embodiment.

FIG. 20 is a piping system diagram of a magnetic refrigeration apparatus according to variation A.

FIG. 21 is a piping system diagram of a magnetic refrigeration apparatus according to variation B.

FIG. 22 is a piping system diagram of a magnetic refrigeration apparatus according to variation C.

FIG. 23 is a piping system diagram of a magnetic refrigeration apparatus according to variation D.

FIG. 24 is a piping system diagram of a magnetic refrigeration apparatus according to variation E.

FIG. 25 shows a graph corresponding to FIG. 3, related to a magnetic refrigeration apparatus according to variation F.

FIG. 26 is a piping system diagram of a magnetic refrigeration apparatus according to a fifth embodiment.

FIG. 27 is a diagram corresponding to FIG. 26, illustrating the flow of a heating medium in a first action according to the fifth embodiment.

FIG. 28 is a diagram corresponding to FIG. 26, illustrating the flow of a heating medium in a second action according to the fifth embodiment.

FIG. 29 is a diagram corresponding to FIG. 26, illustrating the flow of a heating medium in a third action according to the fifth embodiment.

FIG. 30 is a diagram corresponding to FIG. 26, illustrating the flow of a heating medium in a fourth action according to the fifth embodiment.

FIG. 31 is a schematic view illustrating relationship between operating temperature ranges in different operations of the magnetic refrigeration apparatus according to the fifth embodiment and the characteristics of a plurality of magnetic refrigerators.

FIG. 32 is a piping system diagram of a magnetic refrigeration apparatus according to a sixth embodiment.

FIG. 33 is a diagram corresponding to FIG. 32, illustrating the flow of a heating medium in a first action according to the sixth embodiment.

FIG. 34 is a diagram corresponding to FIG. 32, illustrating the flow of a heating medium in a second action according to the sixth embodiment.

FIG. 35 is a diagram corresponding to FIG. 32 illustrating the flow of a heating medium in a third action according to the sixth embodiment.

FIG. 36 is a diagram corresponding to FIG. 32 illustrating the flow of a heating medium in a fourth action according to the sixth embodiment.

FIG. 37 is a schematic view illustrating operating temperature ranges of a magnetic refrigeration apparatus according to variation G.

FIG. 38 is a piping system diagram of a magnetic refrigeration apparatus according to variation H.

FIG. 39 is a schematic view illustrating operating temperature ranges of the magnetic refrigeration apparatus according to variation H.

FIG. 40 is a piping system diagram of a magnetic refrigeration apparatus according to variation I.

FIG. 41 is a schematic diagram illustrating operating temperature ranges of the magnetic refrigeration apparatus according to variation I.

DETAILED DESCRIPTION OF EMBODIMENT(S

Embodiments of the present disclosure will be described below with reference to the drawings. The following embodiments are merely exemplary ones in nature, and are not intended to limit the scope, applications, or use of the invention.

First Embodiment

A magnetic refrigeration apparatus (1) according to this embodiment controls the temperature of a heating medium using a magnetocaloric effect. The magnetic refrigeration apparatus (1) is applied to an air conditioner, for example. The magnetic refrigeration apparatus (1) is a solid-state refrigeration apparatus configured to control the temperature of a heating medium using a caloric effect.

As illustrated in FIG. 1, the magnetic refrigeration apparatus (1) includes a heating medium circuit (C) filled with the heating medium. The heating medium filling the heating medium circuit (C) is conveyed through the heating medium circuit (C). Examples of the heating medium include a refrigerant, water, and brine.

The magnetic refrigeration apparatus (1) includes, as main components, a plurality of magnetic refrigerators (M) as solid refrigerators, a conveying mechanism (20), a first heat exchanger (31), and a second heat exchanger (32). The magnetic refrigerators (M), the conveying mechanism (20), the first heat exchanger (31), and the second heat exchanger (32) are connected to the heating medium circuit (C).

Magnetic Refrigerator

The magnetic refrigerators (M) include a first magnetic refrigerator (M1) and a second magnetic refrigerator (M2). In the following description, the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) may be collectively referred to as magnetic refrigerators (M).

Each magnetic refrigerator (M) includes a bed (10), a magnetic working substance (11) as a solid refrigerant substance, and a magnetic field modulator (12). The bed (10) is a hollow case or column. The interior of the bed (10) is filled with the magnetic working substance (11). An internal channel (13) through which the heating medium flows back and forth is formed in the bed (10).

The magnetic working substance (11) generates heat if a magnetic field is applied to the magnetic working substance (11) or the intensity of the applied magnetic field increases. The magnetic working substance (11) absorbs heat if the magnetic field is removed from the magnetic working substance (11) or if the intensity of the applied magnetic field decreases. Examples of the material of the magnetic working substance (11) include Gd₅(Ge_0.5Si_0.5)₄, La(Fe_1—xSi_x)₁₃, La(Fe_1—xCo_xSi_y)₁₃, La(Fe_1—xSi_x)₁₃H_y, and Mn(As_0.9Sb_0.1).

The magnetic refrigerators (M) of this embodiment are cascaded magnetic refrigerators. Each magnetic refrigerator (M) has different types of magnetic working substances (11) having different Curie temperatures (details will be described later).

The magnetic field modulator (12) is an induction section configured to cause the magnetic working substance (11) serving as a solid refrigerant substance to produce a caloric effect. The magnetic field modulator (12) applies a magnetic field variation to the magnetic working substance (11). The magnetic field modulator (12) controls the intensity of the magnetic field applied to the magnetic working substance (11). The magnetic field modulator (12) is comprised of an electromagnet capable of modulating a magnetic field, for example. The magnetic field modulator (12) performs a first modulation action and a second modulation action. In the first modulation action, a magnetic field is applied to the magnetic working substance (11), or the intensity of the applied magnetic field is increased. In the second modulation action, the magnetic field applied to the magnetic working substance (11) is removed, or the intensity of the applied magnetic field is reduced.

Conveying Mechanism

The conveying mechanism (20) reciprocally conveys the heating medium in the heating medium circuit (C). The conveying mechanism (20) includes a reciprocating pump (21). The reciprocating pump (21) is configured as a piston pump. The reciprocating pump (21) includes a pump case (22), a piston (23), and a driving mechanism (not shown). The piston (23) is disposed inside the pump case (22). The piston (23) partitions the inside of the pump case (22) into two chambers. The reciprocating pump (21) has a first opening (24) and a second opening (25). One of the chambers of the pump case (22) communicates with the first opening (24), and the other chamber communicates with the second opening (25).

The driving mechanism includes a rod coupled to the piston (23), a crank coupled to the rod, and an electric motor configured to drive the crank. In response to the rotation of the crank by the electric motor, the rod moves forward and backward. This allows the piston (23) to reciprocate inside the pump case (22).

The conveying mechanism (20) alternately and repeatedly performs a first conveying action and a second conveying action. In the first conveying action shown in FIG. 5, the piston (23) moves toward the first opening (24). Then, the heating medium in the pump case (22) is discharged from the first opening (24). At the same time, the heating medium is sucked into the pump case (22) through the second opening (25). In the second conveying action shown in FIG. 6, the piston (23) moves toward the second opening (25). Then, the heating medium in the pump case (22) is discharged from the second opening (25). At the same time, the heating medium is sucked into the pump case (22) through the first opening (24).

First Heat Exchanger and Second Heat Exchanger

The first heat exchanger (31) and the second heat exchanger (32) exchange heat between the heating medium flowing through the heating medium circuit (C) and a target fluid. In this embodiment, the first and second heat exchangers (31) and (32) are air heat exchangers. The first and second heat exchangers (31) and (32) exchange heat between the heating medium in the heating medium circuit (C) and the air.

The first heat exchanger (31) constitutes a low-temperature heat exchanger. In other words, the first heat exchanger (31) is a heat absorber that takes heat from the air to the heating medium. The second heat exchanger (32) constitutes a high-temperature heat exchanger. In other words, the second heat exchanger (32) is a radiator that dissipates heat from the heating medium to the air. The first heat exchanger (31) corresponds to a first heat exchange section of the present disclosure. The second heat exchanger (32) corresponds to a second heat exchange section of the present disclosure.

Heating Medium Circuit

The heating medium circuit (C) includes, as main components, a first channel (40), a second channel (50), a first conveying channel (61), and a second conveying channel (62). The heating medium circuit (C) includes a plurality of bypass mechanisms (B).

First Channel

The first channel (40) is a passage for supplying the heating medium to the first heat exchanger (31). An inlet end of the first channel (40) is connected to an outlet end of the second heat exchanger (32). An outlet end of the first channel (40) is connected to an inlet end of the first heat exchanger (31). The first channel (40) includes a first upstream path (41), a first intermediate path (42), and a first downstream path (43). The first channel (40) includes internal channels (13) of the magnetic refrigerators (M). The first channel (40) connects the first upstream path (41), the internal channel (13) of the first magnetic refrigerator (M1), the first intermediate path (42), the internal channel (13) of the second magnetic refrigerator (M2), and the first downstream path (43) in this order.

The first channel (40) has a first check valve (CV1) provided on the upstream side of each of the magnetic refrigerators (M). The first channel (40) also has a second check valve (CV2) provided on the downstream side of each of the magnetic refrigerators (M). The first check valves (CV1) and the second check valves (CV2) allow the heating medium to flow from the second heat exchanger (32) to the first heat exchanger (31), and prohibit the heating medium from flowing in the opposite direction.

Second Channel

The second channel (50) is a passage for supplying the heating medium to the second heat exchanger (32). An inlet end of the second channel (50) is connected to an outlet end of the first heat exchanger (31). An outlet end of the second channel (50) is connected to an inlet end of the second heat exchanger (32). The second channel (50) includes a second upstream flow path (51), a second intermediate flow path (52), and a second downstream flow path (53). The second channel (50) includes internal channels (13) of the magnetic refrigerators (M). The second channel (50) connects the second upstream path (51), the internal channel (13) of the second magnetic refrigerator (M2), the second intermediate path (52), the internal channel (13) of the first magnetic refrigerator (M1), and the second downstream path (53) in this order.

The second channel (50) has a third check valve (CV3) provided on the upstream side of each of the magnetic refrigerators (M). The second channel (50) also has a fourth check valve (CV4) provided on the downstream side of each of the magnetic refrigerators (M). The third check valves (CV3) and the fourth check valves (CV4) allow the heating medium to flow from the first heat exchanger (31) to the second heat exchanger (32), and prohibit the heating medium from flowing in the opposite direction.

The first channel (40) and the second channel (50) allow the heating medium to flow only in the directions opposite to each other.

First Conveying Channel

An inlet end of the first conveying channel (61) is connected to the first opening (24) of the reciprocating pump (21). An outlet end of the first conveying channel (61) is connected to the second upstream channel (51) between the first heat exchanger (31) and an inlet end of a third bypass channel (67).

Second Conveying Channel

An inlet end of the second conveying channel (62) is connected to the second opening (25) of the reciprocating pump (21). An outlet end of the second conveying channel (62) is connected to the first upstream path (41) between the second heat exchanger (32) and an inlet end of a first bypass channel (63).

Bypass Mechanism

The bypass mechanism s (B) include a first bypass mechanism (B1), a second bypass mechanism (B2), a third bypass mechanism (B3), and a fourth bypass mechanism (B4). Each bypass mechanism (B) in the heating medium circuit (C) switches between an action of making the heating medium flow through the magnetic refrigerator (M) and an action of making the heating medium bypass the magnetic refrigerator (M).

First Bypass Mechanism

The first bypass mechanism (B1) is connected to the first channel (40). The first bypass mechanism (B1) is associated with the internal channel (13) of the first magnetic refrigerator (M1). The first bypass mechanism (B1) switches between the channel where the heating medium in the first channel (40) flows through the internal channel (13) of the first magnetic refrigerator (M1) and the channel where the heating medium in the first channel (40) bypasses the internal channel (13) of the first magnetic refrigerator (M1).

Specifically, the first bypass mechanism (B1) includes a first bypass channel (63) and a first control valve (64). An inlet end of the first bypass channel (63) is connected to the first upstream path (41) between a junction of the first upstream path (41) with the second conveying channel (62) and the first check valve (CV1) near the first magnetic refrigerator (M1). An outlet end of the first bypass channel (63) is connected to the first intermediate path (42) between the second check valve (CV2) near the first magnetic refrigerator (M1) and the first check valve (CV1) near the second magnetic refrigerator (M2).

The first bypass channel (63) includes a first upstream portion (63a) and a first downstream portion (63b). The first downstream portion (63b) of the first bypass channel (63) also serves as a second upstream portion (65a) of the second bypass channel (65). The first control valve (64) is an on-off valve that opens and closes the first bypass channel (63). The first control valve (64) is provided in the first upstream portion (63a).

Second Bypass Mechanism

The second bypass mechanism (B2) is connected to the first channel (40). The second bypass mechanism (B2) is associated with the internal channel (13) of the second magnetic refrigerator (M2). The second bypass mechanism (B2) switches between the channel where the heating medium in the first channel (40) flows through the internal channel (13) of the second magnetic refrigerator (M2) and the channel where the heating medium in the first channel (40) bypasses the internal channel (13) of the second magnetic refrigerator (M2).

Specifically, the second bypass mechanism (B2) includes a second bypass channel (65) and a second control valve (66). An outlet end of the second bypass channel (65) is connected to the first intermediate path (42) between the second check valve (CV2) near the first magnetic refrigerator (M1) and the first check valve (CV1) near the second magnetic refrigerator (M2). An outlet end of the second bypass channel (65) is connected to the first downstream path (43) between the second check valve (CV2) near the second magnetic refrigerator (M2) and the first heat exchanger (31).

The second bypass channel (65) includes a second upstream portion (65a) and a second downstream portion (65b). The second control valve (66) is an on-off valve that opens and closes the second bypass channel (65). The second control valve (66) is provided in the second downstream portion (65b).

Third Bypass Mechanism

The third bypass mechanism (B3) is connected to the second channel (50). The third bypass mechanism (B3) is associated with the internal channel (13) of the second magnetic refrigerator (M2). The third bypass mechanism (B3) switches between the channel where the heating medium in the second channel (50) flows through the internal channel (13) of the second magnetic refrigerator (M2) and the channel where the heating medium in the second channel (50) bypasses the internal channel (13) of the second magnetic refrigerator (M2).

Specifically, the third bypass mechanism (B3) includes a third bypass channel (67) and a third control valve (68). An inlet end of the third bypass channel (67) is connected to the second upstream channel (51) between a junction of the second upstream channel (51) with the first conveying channel (61) and the third check valve (CV3) near the second magnetic refrigerator (M2). An outlet end of the third bypass channel (67) is connected to the second intermediate path (52) between the fourth check valve (CV4) near the second magnetic refrigerator (M2) and the third check valve (CV3) near the first magnetic refrigerator (M1).

The third bypass channel (67) includes a third upstream portion (67a) and a third downstream portion (67b). The third downstream portion (67b) of the third bypass channel (67) also serves as a fourth upstream portion (69a) of a fourth bypass channel (69). The third control valve (68) is an on-off valve that opens and closes the third bypass channel (67). The third control valve (68) is provided in the third upstream portion (67a).

Fourth Bypass Mechanism

The fourth bypass mechanism (B4) is connected to the second channel (50). The fourth bypass mechanism (B4) is associated with the internal channel (13) of the first magnetic refrigerator (M1). The fourth bypass mechanism (B4) switches between the channel where the heating medium in the second channel (50) flows through the internal channel (13) of the first magnetic refrigerator (M1) and the channel where the heating medium in the second channel (50) bypasses the internal channel (13) of the first magnetic refrigerator (M1).

Specifically, the fourth bypass mechanism (B4) includes a fourth bypass channel (69) and a fourth control valve (70). An inlet end of the fourth bypass channel (69) is connected to the second intermediate path (52) between the fourth check valve (CV4) near the second magnetic refrigerator (M2) and the third check valve (CV3) near the first magnetic refrigerator (M1). An outlet end of the fourth bypass channel (69) is connected to the second downstream path (53) between the fourth check valve (CV4) near the first magnetic refrigerator (M1) and the second heat exchanger (32).

The fourth bypass channel (69) includes a fourth upstream portion (69a) and a fourth downstream portion (69b). The fourth control valve (70) is an on-off valve that opens and closes the fourth bypass channel (69). The fourth control valve (70) is provided in the fourth downstream portion (69b).

The first control valve (64), the second control valve (66), the third control valve (68), and the fourth control valve (70) may be flow regulating valves capable of controlling the flow rate.

Controller

As illustrated in FIG. 2, the magnetic refrigeration apparatus (1) includes a controller (100). The controller (100) controls the magnetic field modulator (12), the conveying mechanism (20), and the bypass mechanisms (B). More specifically, the controller (100) controls each of the control valves (64, 66, 68, 70) of the bypass mechanisms (B) in accordance with an operation command. The controller (100) includes a microcomputer and a memory device (specifically, a semiconductor memory) storing software for operating the microcomputer.

Details of Magnetic Working Substance

The first and second magnetic refrigerators (M1) and (M2) are cascaded magnetic refrigerators. Each of the first and second magnetic refrigerators (M1) and (M2) has different types (three types in this example) of magnetic working substances (11) having different Curie temperatures. The Curie temperature is the temperature at which the magnetic working substance (11) has the highest magnetocaloric effect. The cascaded magnetic refrigerator (M) may have two or four or more magnetic working substances (11).

As illustrated in FIG. 3, the second magnetic refrigerator (M2) includes a first magnetic working substance (11a), a second magnetic working substance (11b), and a third magnetic working substance (11c) arranged in this order from a low-temperature end to a high-temperature end of the magnetic refrigerator (M2). The first magnetic refrigerator (M1) includes a fourth magnetic working substance (11d), a fifth magnetic working substance (11e), and a sixth magnetic working substance (11f) arranged in this order from a low-temperature end to a high-temperature end of the first magnetic refrigerator (M1). In the graphs of FIG. 3, curves a, b, and c indicate operating temperature ranges of the first magnetic working substance (11a), the second magnetic working substance (11b), and the third magnetic working substance (11c), respectively, and curves d, e, and f indicate operating temperature ranges of the fourth magnetic working substance (11d), the fifth magnetic working substance (11e), and the sixth magnetic working substance (11f), respectively.

Assume that the first, second and third magnetic working substances (11a), (11b), and (11c) have the Curie temperatures Tc1, Tc2, and Tc3, respectively, and the fourth, fifth, and sixth magnetic working substances (11d), (11e), and (11f) have the Curie-temperatures Tc4, Tc5, and Tc6, respectively, the relationship of Tc1<Tc2<Tc3<Tc4<Tc5<Tc6 is met.

In the first channel (40) and the second channel (50), the magnetic refrigerators (M) (two magnetic refrigerators in this example) are connected in series with the magnetic refrigerators (M) being arranged in an ascending order of average values of the Curie temperatures. Specifically, the average value T1 of the Curie temperature of the first magnetic refrigerator (M1) is greater than the average value T2 of the Curie temperature of the second magnetic refrigerator (M2). In this example, T1 is expressed by the relational expression T1 = (Tc4 + Tc5 + Tc6)/3. T2 is expressed by the relational expression T2 = (Tcl + Tc2 + Tc3)/3.

In the heating medium circuit (C), the operating temperature ranges of the adjacent magnetic refrigerators (M) partially overlap each other. Specifically, the operating temperature range of the third magnetic working substance (11c) of the second magnetic refrigerator (M2) partially overlaps the operating temperature range of the fourth magnetic working substance (11d) of the first magnetic refrigerator (M1). The third magnetic working substance (11c) is a magnetic working substance at the end of the second magnetic refrigerator (M2). The fourth magnetic working substance (11d) is a magnetic working substance at the end of the first magnetic refrigerator (M1). More specifically, the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) are configured to meet the following relationship.

In the first and second magnetic refrigerators (M1) and (M2), attention is paid to the magnetic working substances at the adjacent ends, i.e., the third magnetic working substance (11c) and the fourth magnetic working substance (11d). Em2 denotes the magnetocaloric effect corresponding to the Curie temperature Tc3 of the third magnetic working substance (11c), and Em1 denotes the magnetocaloric effect corresponding to the Curie temperature Tc4 of the fourth magnetic working substance (11d). Em2 is the maximum value of the magnetocaloric effect of the third magnetic working substance (11c). Em1 is the maximum value of the magnetocaloric effect of the fourth magnetic working substance (11d). Eave is the average value of Em1 and Em2. Ep denotes the maximum value of the magnetocaloric effect in an overlapping area A of the operating temperature ranges of the third magnetic working substance (11c) and the fourth magnetic working substance (11d). In FIG. 4, the overlapping area A is hatched.

In this example, the magnetocaloric effect Ep is equal to or more than ½ of the average value Eave of Em1 and Em2. In other words, the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) are configured to meet the following formula (1).

$\text{Ep}\ge \left(\left(\text{Em1+Em2}\right)/2\right)\times \left(1/2\right)·$

In this example, the operating temperature ranges of the magnetic working substances (11c, 11d) at the adjacent ends partially overlap each other. Note that the operating temperature ranges of the magnetic working substances (11c, 11d) at the adjacent ends may completely overlap each other. Also in this case, the adjacent magnetic refrigerators (M) meet the above formula (1).

Operation

The operation of the magnetic refrigeration apparatus (1) will be described with reference to FIGS. 5 to 10. In FIG. 5 and subsequent figures, the magnetic field modulator (12) is not shown. The magnetic refrigeration apparatus (1) alternately repeats a heating action and a cooling action. The heating action includes a normal heating action, a first bypass heating action, and a second bypass heating action. The cooling action includes a normal cooling action, a first bypass cooling action, and a second bypass cooling action. When normally operated, the magnetic refrigeration apparatus (1) alternately repeats the normal heating action and the normal cooling action. The first bypass heating action, the second bypass heating action, the first bypass cooling action, and the second bypass cooling action are appropriately performed depending on the thermal load, operating conditions, and required capacity of the magnetic refrigeration apparatus (1). In the following description, the first bypass heating action, the second bypass heating action, the first bypass cooling action, and the second bypass cooling action may be collectively referred to as a bypass action.

Normal Heating Action

In the normal heating action shown in FIG. 5, each of the magnetic field modulators (12) of the first and second magnetic refrigerators (M1) and (M2) performs the first modulation action. The conveying mechanism (20) performs the first conveying action. The controller (100) closes the first control valve (64), the second control valve (66), the third control valve (68), and the fourth control valve (70).

In the normal heating action, the heating medium flowing through the second channel (50) is heated by the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2). The heated heating medium is supplied to the second heat exchanger (32) serving as a radiator. The heating medium dissipates heat to the air in the second heat exchanger (32). In the drawings, the heat exchanger serving as a radiator is hatched.

More specifically, the heating medium at a relatively low temperature discharged from the first opening (24) of the reciprocating pump (21) flows through the first conveying channel (61), the second upstream path (51), and the internal channel (13) of the second magnetic refrigerator (M2) in this order. In the second magnetic refrigerator (M2), the heating medium is heated by the first magnetic working substance (11a), the second magnetic working substance (11b), and the third magnetic working substance (11c) in this order. In the second magnetic refrigerator (M2), the magnetic working substances (11a, 11b, 11c) are arranged in an ascending order of the Curie-temperature from the low-temperature end to the high-temperature end. Thus, each of the magnetic working substances (11a11b, 11c) of the second magnetic refrigerator (M2) can produce a relatively large magnetocaloric effect.

The heating medium heated in the second magnetic refrigerator (M2) flows through the second intermediate path (52) and the internal channel (13) of the first magnetic refrigerator (M1) in this order. The heating medium in the first magnetic refrigerator (M1) is heated by the fourth magnetic working substance (11d), the fifth magnetic working substance (11e), and the sixth magnetic working substance (11f) in this order. In the first magnetic refrigerator (M1), the magnetic working substances (11d, 11e, 11f) are arranged in an ascending order of the Curie temperature from the low-temperature end to the high-temperature end. Thus, each of the magnetic working substances (11d, 11e, 11f) of the first magnetic refrigerator (M1) can produce a relatively large magnetocaloric effect.

The heating medium heated in the first magnetic refrigerator (M1) flows through the second downstream path (53) and the second heat exchanger (32) in this order. The heating medium dissipates heat to the air in the second heat exchanger (32) to heat the air. The heating medium that has dissipated heat in the second heat exchanger (32) flows through the second conveying channel (62) and is sucked into the second opening (25) of the reciprocating pump (21).

Normal Cooling Action

In the normal cooling action shown in FIG. 6, each of the magnetic field modulators (12) of the first and second magnetic refrigerators (M1) and (M2) performs the second modulation action. The conveying mechanism (20) performs the second conveying action. The controller (100) closes the first control valve (64), the second control valve (66), the third control valve (68), and the fourth control valve (70).

In the normal cooling action, the heating medium flowing through the first channel (40) is cooled by the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2). The cooled heating medium is supplied to the first heat exchanger (31) serving as a heat absorber. The heating medium absorbs heat from the air in the first heat exchanger (31). In the drawings, the heat exchanger serving as a heat absorber is dotted.

More specifically, the heating medium at a relatively high temperature discharged from the second opening (25) of the reciprocating pump (21) flows through the second conveying channel (62), the first upstream path (41), and the first magnetic refrigerator (M1) in this order. The heating medium in the first magnetic refrigerator (M1) is cooled by the sixth magnetic working substance (11f), the fifth magnetic working substance (11e), and the fourth magnetic working substance (11d) in this order. In the first magnetic refrigerator (M1), the magnetic working substances (11d, 11e, 11f) are arranged in a descending order of the Curie temperature from the high-temperature end to the low-temperature end. Thus, each of the magnetic working substances (11d, 11e, 11f) of the first magnetic refrigerator (M1) can produce a relatively large magnetocaloric effect.

The heating medium cooled in the first magnetic refrigerator (M1) flows through the first intermediate path (42) and the internal channel (13) of the second magnetic refrigerator (M2) in this order. The heating medium in the second magnetic refrigerator (M2) is cooled by the third magnetic working substance (11c), the second magnetic working substance (11b), and the first magnetic working substance (11a) in this order. In the second magnetic refrigerator (M2), the magnetic working substances (11a, 11b, 11c) are arranged in a descending order of the Curie temperature from the high-temperature end to the low-temperature end. Thus, each of the magnetic working substances (11a, 11b, 11c) of the second magnetic refrigerator (M2) can produce a relatively large magnetocaloric effect.

The heating medium cooled in the second magnetic refrigerator (M2) flows through the first downstream path (43) and the first heat exchanger (31) in this order. The heating medium absorbs heat from the air in the first heat exchanger (31) to cool the air. The heating medium that has absorbed heat in the first heat exchanger (31) flows through the first conveying channel (61) and is sucked into the first opening (24) of the reciprocating pump (21).

First Bypass Heating Action

In the first bypass heating action shown in FIG. 7, the magnetic field modulator (12) of the first magnetic refrigerator (M1) performs the first modulation action. The second magnetic refrigerator (M2) does not substantially operate. The conveying mechanism (20) performs the first conveying action. The controller (100) closes the first control valve (64), the second control valve (66), and the fourth control valve (70), and opens the third control valve (68).

In the first bypass heating action, the heating medium flowing through the second channel (50) bypasses the second magnetic refrigerator (M2). Specifically, the heating medium in the second upstream path (51) flows through the third bypass channel (67), the second intermediate path (52), and the first magnetic refrigerator (M1) in this order. The heating medium heated in the first magnetic refrigerator (M1) flows through the second downstream path (53) and dissipates heat to the air in the second heat exchanger (32).

In the first bypass heating action, the third control valve (68) is open, and the heating medium in the second upstream path (51) hardly flows through the second magnetic refrigerator (M2). This is because the internal channel (13) of the second magnetic refrigerator (M2) is filled with the magnetic working substance (11), and has an extremely high flow resistance.

Second Bypass Heating Action

In the second bypass heating action shown in FIG. 8, the magnetic field modulator (12) of the second magnetic refrigerator (M2) performs the first modulation action. The first magnetic refrigerator (M1) does not substantially operate. The conveying mechanism (20) performs the first conveying action. The controller (100) closes the first control valve (64), the second control valve (66), and the third control valve (68), and opens the fourth control valve (70).

In the second bypass heating action, the heating medium flowing through the second channel (50) bypasses the first magnetic refrigerator (M1). Specifically, the heating medium in the second upstream path (51) is heated in the second magnetic refrigerator (M2), flows through the second intermediate path (52), the fourth bypass channel (69), and the second downstream path (53), and dissipates heat to the air in the second heat exchanger (32).

In the second bypass heating action, the fourth control valve (70) is open, and the heating medium in the second intermediate path (52) hardly flows through the first magnetic refrigerator (M1). This is because the internal channel (13) of the first magnetic refrigerator (M1) is filled with the magnetic working substance (11), and has an extremely high flow resistance.

First Bypass Cooling Action

In the first bypass cooling action shown in FIG. 9, the magnetic field modulator (12) of the second magnetic refrigerator (M2) performs the second modulation action. The first magnetic refrigerator (M1) is substantially stopped. The conveying mechanism (20) performs the second conveying action. The controller (100) closes the second control valve (66), the third control valve (68), and the fourth control valve (70), and opens the first control valve (64).

In the first bypass cooling action, the heating medium flowing through the first channel (40) bypasses the first magnetic refrigerator (M1). Specifically, the heating medium in the first upstream path (41) flows through the first bypass channel (63), the first intermediate path (42), and the second magnetic refrigerator (M2) in this order. The heating medium cooled in the second magnetic refrigerator (M2) flows through the first downstream path (43) and absorbs heat from the air in the first heat exchanger (31).

In the first bypass cooling action, the first control valve (64) is open, and the heating medium in the first upstream path (41) hardly flows through the first magnetic refrigerator (M1). This is because the internal channel (13) of the first magnetic refrigerator (M1) is filled with the magnetic working substance (11), and has an extremely high flow resistance.

Second Bypass Cooling Action

In the second bypass cooling action shown in FIG. 10, the magnetic field modulator (12) of the first magnetic refrigerator (M1) performs the second modulation action. The second magnetic refrigerator (M2) is substantially stopped. The conveying mechanism (20) performs the second conveying action. The controller (100) closes the first control valve (64), the third control valve (68), and the fourth control valve (70), and opens the second control valve (66).

In the second bypass cooling action, the heating medium flowing through the first channel (40) bypasses the second magnetic refrigerator (M2). Specifically, the heating medium in the first upstream path (41) is cooled in the first magnetic refrigerator (M1), flows through the first intermediate path (42), the second bypass channel (65), and the first downstream path (43), and absorbs heat from the air in the first heat exchanger (31).

In the second bypass cooling action, the second control valve (66) is open, and the heating medium in the first intermediate path (42) hardly flows through the second magnetic refrigerator (M2). This is because the internal channel (13) of the second magnetic refrigerator (M2) is filled with the magnetic working substance (11), and has an extremely high flow resistance.

Advantages of First Embodiment

The first embodiment provides the following advantages and effects.

Bypass Mechanism

The magnetic refrigeration apparatus (1) includes the bypass mechanism (B) that switches between the channel where the heating medium flows through the magnetic refrigerator (M) and the channel where the heating medium bypasses the magnetic refrigerator (M). Thus, the heating medium is not heated in a certain magnetic refrigerator (M) in the heating action, making the entire heating capacity of the magnetic refrigeration apparatus (1) adjustable. The heating medium is not cooled in a certain magnetic refrigerator (M) in the cooling action, making the entire cooling capacity of the magnetic refrigeration apparatus (1) adjustable.

In the magnetic refrigeration apparatus (1), the bypass mechanism (B) is provided for each of the magnetic refrigerators (M) in both of the first channel (40) and the second channel (50). Specifically, the first channel (40) is provided with the first bypass mechanism (B1) corresponding to the first magnetic refrigerator (M1). The first channel (40) is provided with the second bypass mechanism (B2) corresponding to the second magnetic refrigerator (M2). The second channel (50) is provided with the third bypass mechanism (B3) corresponding to the second magnetic refrigerator (M2). The second channel (50) is provided with the fourth bypass mechanism (B4) corresponding to the first magnetic refrigerator (M1). Thus, in the heating action, switching is appropriately made between the normal heating action, the first bypass heating action, and the second bypass heating action described above. This allows fine control of the entire heating capacity of the magnetic refrigeration apparatus (1). In the cooling action, switching is appropriately made between the normal cooling action, the first bypass cooling action, and the second bypass cooling action described above. This allows fine control of the entire cooling capacity of the magnetic refrigeration apparatus (1).

First Channel and Second Channel

When the bypass mechanisms (B) are provided, the heating medium may accumulate in the bypass channels (63, 65, 67, 69). Specifically, for example, in the second bypass heating action shown in FIG. 8, a relatively high-temperature heating medium accumulates in the fourth bypass channel (69). If the normal cooling action shown in FIG. 6 is performed in this state, for example, the heating medium flows through the first channel (40) without passing through the second channel (50). Thus, in the normal cooling action, the heating medium supplied to the first heat exchanger (31) is not mixed with the heating medium accumulated in the fourth bypass channel (69). This can reduce the heat loss resulting from the mixing of the heating media.

Likewise, in the second bypass cooling action shown in FIG. 10, for example, a relatively low-temperature heating medium accumulates in the second bypass channel (65). If the normal heating action shown in FIG. 5 is performed in this state, for example, the heating medium flows through the second channel (50) without passing through the first channel (40). Thus, in the normal heating action, the heating medium supplied to the second heat exchanger (32) is not mixed with the heating medium accumulated in the second bypass channel (65). This can reduce the heat loss resulting from the mixing of the heating media.

Curie Temperature

In the first channel (40) and the second channel (50), the magnetic refrigerators (M) (two magnetic refrigerators in this example) are connected in series with the magnetic refrigerators (M) being arranged in an ascending order of the average values of the Curie temperatures. Specifically, as illustrated in FIG. 3, the average value T2 of the Curie temperatures of all the magnetic working substances (11) of the second magnetic refrigerator (M2) is greater than the average value T1 of the Curie temperatures of all the magnetic working substances (11) of the first magnetic refrigerator (M1). In the normal heating action, the heating medium in the second channel (50) flows through the second magnetic refrigerator (M2) and the first magnetic refrigerator (M1) in this order, bringing the temperature of the heating medium flowing through the magnetic refrigerators (M) closer to the average value of the Curie temperatures of the magnetic refrigerators (M). This can increase the magnetocaloric effect of the magnetic refrigerators (M), increasing the heating capacity.

In the cooling action, the heating medium in the first channel (40) flows through the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) in this order, bringing the temperature of the heating medium flowing through the magnetic refrigerators (M) closer to the average value of the Curie temperature of the magnetic refrigerators (M). This can increase the magnetocaloric effect of the magnetic refrigerators (M), increasing the cooling capacity.

Each of the magnetic refrigerators (M) is a cascaded magnetic refrigerator including different types of magnetic working substances (11) arranged from the low-temperature end to the high-temperature end of the magnetic refrigerator (M) in an ascending order of the Curie temperature. Thus, in the heating action, the heating medium in the second channel (50) sequentially flows from the low-temperature end to the high-temperature end of each magnetic refrigerator (M), bringing the temperature of the heating medium flowing through the magnetic working substances (11) closer to the Curie temperatures of the magnetic working substances (11). This can increase the magnetocaloric effect of the magnetic working substances (11), increasing the heating capacity.

In the cooling action, the heating medium in the first channel (40) sequentially flows from the high-temperature end to the low-temperature end of each of the magnetic working substances (11), bringing the temperature of the heating medium flowing through the magnetic working substances (11) closer to the Curie temperatures of the magnetic working substances (11). This can increase the magnetocaloric effect of the magnetic working substances (11), increasing the cooling capacity.

Operating Temperature Range

As illustrated in FIG. 4, the operating temperature ranges of the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) adjacent to each other partially overlap each other. Specifically, the maximum value Ep of the magnetocaloric effect in the overlapping area A of the operating temperature ranges of the magnetic working substances (11c, 11d) at the adjacent ends of the magnetic refrigerators (M) is equal to or more than ½ of the average value Eave of the maximum values of the magnetocaloric effect of the magnetic working substances (11c, 11d) at the adjacent ends of the magnetic refrigerators (M). Thus, the temperature of the heating medium can be kept from deviating from the operating temperature ranges of the magnetic refrigerators (M) in spite of the temperature change of the heating medium caused by the switching from the normal action (in which the heating medium flows through the magnetic refrigerators (M)) to the bypass action.

Specifically, for example, assume that the first bypass heating action shown in FIG. 7 is performed after the normal heating action shown in FIG. 5 and the subsequent predetermined cooling action. In this case, the heating medium in the second channel (50) bypasses the second magnetic refrigerator (M2) and flows through the first magnetic refrigerator (M1). Thus, the temperature of the heating medium flowing through the first magnetic refrigerator (M1) during the first bypass heating action is lower than the temperature of the heating medium flowing through the first magnetic refrigerator (M1) during the normal heating action. On the other hand, the operating temperature range of the fourth magnetic working substance (11d) of the first magnetic refrigerator (M1) overlaps with the operating temperature range of the third magnetic working substance (11c) of the second magnetic refrigerator (M2). Thus, the temperature of the heating medium flowing through the first magnetic refrigerator (M1) can be kept from deviating from the operating temperature range during the first bypass heating action. In particular, in this embodiment, the operating temperature ranges of the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) overlap each other to meet the relationship of Ep ≥ ((Em1+Em2)/2) × (½). This can sufficiently keep the temperature of the heating medium flowing through the first magnetic refrigerator (M1) from deviating from the operating temperature range during the first bypass heating action.

Likewise, for example, assume that the first bypass cooling action shown in FIG. 9 is performed after the normal cooling action shown in FIG. 6 and the subsequent predetermined heating action. In this case, the heating medium in the first channel (40) bypasses the first magnetic refrigerator (M1) and flows through the second magnetic refrigerator (M2). Thus, the temperature of the heating medium flowing through the second magnetic refrigerator (M2) during the first bypass cooling action is higher than the temperature of the heating medium flowing through the first magnetic refrigerator (M1) during the normal cooling action. On the other hand, the operating temperature range of the third magnetic working substance (11c) of the second magnetic refrigerator (M2) overlaps with the operating temperature range of the fourth magnetic working substance (11d) of the first magnetic refrigerator (M1). Thus, the temperature of the heating medium flowing through the second magnetic refrigerator (M2) can be kept from deviating from the operating temperature range during the first bypass cooling action. In particular, in this embodiment, the operating temperature ranges of the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) overlap each other to meet the relationship of Ep ≥ ((Em 1 + Em2)/2) x (½). This can sufficiently keep the temperature of the heating medium flowing through the second magnetic refrigerator (M2) from deviating from the operating temperature range during the first bypass cooling action.

Further, this configuration can keep the temperature of the heating medium from deviating from the operating temperature range of the magnetic refrigerator (M) in spite of the temperature change of the heating medium flowing through a certain magnetic refrigerator (M) caused by the switching from the bypass action to the normal action.

Second Embodiment

A magnetic refrigeration apparatus (1) of the second embodiment is different from the magnetic refrigeration apparatus of the first embodiment in the configuration of the magnetic refrigerators (M).

As illustrated in FIG. 11, the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) are cascaded magnetic refrigerators. In the second embodiment, the magnetic working substances (11) of the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) have different characteristics. Among the different types (three types in this example) of magnetic working substances (11) in each magnetic refrigerator (M), the magnetic working substances (11a, 11c, 11d, 11f) have wider operating temperature ranges than the magnetic working substances (11b, 11e).

Specifically, in the second magnetic refrigerator (M2), the operating temperature range Wa of the first magnetic working substance (11a) is wider than the operating temperature range Wb of the second magnetic working substance (11b). The operating temperature range We of the third magnetic working substance (11c) is widerthan the operating temperature range Wb of the second magnetic working substance (11b).

The third magnetic working substance (11c) of the second magnetic refrigerator (M2) is an endmost magnetic working substance located at one of ends of the second magnetic refrigerator (M2) facing the adjacent magnetic refrigerator (first magnetic refrigerator (M1)). The second magnetic working substance (11b) of the second magnetic refrigerator (M2) is an intermediate magnetic working substance located in an intermediate portion between the ends of the second magnetic refrigerator (M2).

In the first magnetic refrigerator (M1), the operating temperature range Wd of the fourth magnetic working substance (11d) is wider than the operating temperature range We of the fifth magnetic working substance (11e). The operating temperature range Wf of the sixth magnetic working substance (11f) is wider than the operating temperature range We of the fifth magnetic working substance (11e).

The fourth magnetic working substance (11d) of the first magnetic refrigerator (M1) is an endmost magnetic working substance located at one of ends of the first magnetic refrigerator (M1) facing the adjacent magnetic refrigerator (second magnetic refrigerator (M2)). The fifth magnetic working substance (11e) of the first magnetic refrigerator (M1) is an intermediate magnetic working substance located in an intermediate portion between the ends of the first magnetic refrigerator (M1).

When the endmost magnetic working substances (11c, 11d) have wider operating temperature ranges than the intermediate magnetic working substances (11b, 11e), the temperature of the heating medium can be kept from deviating from the operating temperature range of the magnetic refrigerator (M) during the bypass action.

Specifically, for example, assume that the first bypass heating action shown in FIG. 7 is performed after the normal heating action shown in FIG. 5 and the subsequent predetermined cooling action. In this case, as described above, the temperature of the heating medium flowing through the first magnetic refrigerator (M1) is lower than the temperature of the heating medium flowing through the first magnetic refrigerator (M1) during the normal heating action. On the other hand, the fourth magnetic working substance (11d) of the first magnetic refrigerator (M1) has a relatively wide operating temperature range. Thus, the temperature of the heating medium flowing through the first magnetic refrigerator (M1) can be kept from deviating from the operating temperature range during the first bypass heating action.

Likewise, for example, assume that the first bypass cooling action shown in FIG. 9 is performed after the normal cooling action shown in FIG. 6 and the subsequent predetermined heating action. In this case, as described above, the temperature of the heating medium flowing through the second magnetic refrigerator (M2) during the first bypass cooling action is higher than the temperature of the heating medium flowing through the first magnetic refrigerator (M1) during the normal cooling action. On the other hand, the third magnetic working substance (11c) of the second magnetic refrigerator (M2) has a relatively wide operating temperature range. Thus, the temperature of the heating medium flowing through the second magnetic refrigerator (M2) can be kept from deviating from the operating temperature range during the first bypass cooling action.

Further, this configuration can keep the temperature of the heating medium from deviating from the operating temperature range of the magnetic refrigerator (M) in spite of the temperature change of the heating medium flowing through a certain magnetic refrigerator (M) caused by the switching from the bypass action to the normal action.

In this example, the operating temperature range Wa of the first magnetic working substance (11a) may be equal to or narrower than the operating temperature range Wb of the second magnetic working substance (11b). The operating temperature range Wf of the sixth magnetic working substance (11f) may be equal to or narrower than the operating temperature range We of the fifth magnetic working substance (11e).

In this example, the magnetic refrigerator (M) may have a plurality of intermediate magnetic working substances. In this case, the operating temperature range of the endmost magnetic working substance may be wider than the operating temperature range of at least one of the plurality of intermediate magnetic working substances. Preferably, the operating temperature range of the endmost magnetic working substance is wider than the operating temperature ranges of all the intermediate magnetic working substances.

Variation of Second Embodiment

In a variation of the second embodiment, the magnetic refrigerators (M) are configured differently from the magnetic refrigerators (M) of the second embodiment. The magnetic refrigerators (M) according to the variation of the second embodiment are cascaded magnetic refrigerators. In each magnetic refrigerator (M), the maximum value of the magnetocaloric effect of the endmost magnetic working substance (11c, 11d) is greater than the maximum value of the magnetocaloric effect of the intermediate magnetic working substance (11b, 11e). Specifically, the maximum value of the magnetocaloric effect of the third magnetic working substance (11c) is greater than the maximum value of the magnetocaloric effect of the second magnetic working substance (11b). The maximum value of the magnetocaloric effect of the fourth magnetic working substance (11d) is greater than the maximum value of the magnetocaloric effect of the fifth magnetic working substance (11e).

When the maximum value of the magnetocaloric effect of the endmost magnetic working substance (11c, 11d) is made larger than the maximum value of the magnetocaloric effect of the intermediate magnetic working substance (11b, 11e), the temperature of the heating medium can be kept from deviating from the operating temperature range of the magnetic refrigerator (M) during the bypass action.

Specifically, for example, assume that the first bypass heating action shown in FIG. 7 is performed after the normal heating action shown in FIG. 5 and the subsequent predetermined cooling action. In this case, as described above, the temperature of the heating medium flowing through the first magnetic refrigerator (M1) is lower than the temperature of the heating medium flowing through the first magnetic refrigerator (M1) during the normal heating action. On the other hand, the fourth magnetic working substance (11d) of the first magnetic refrigerator (M1) has a relatively large magnetocaloric effect, and thus, can sufficiently heat the heating medium. As a result, the temperature of the heating medium flowing through the first magnetic refrigerator (M1) can be kept from deviating from the operating temperature range of the first magnetic refrigerator (M1).

For example, assume that the first bypass cooling action shown in FIG. 9 is performed after the normal cooling action shown in FIG. 6 and the subsequent predetermined heating action. In this case, as described above, the temperature of the heating medium flowing through the second magnetic refrigerator (M2) is higher than the temperature of the heating medium flowing through the second magnetic refrigerator (M2) during the normal cooling action. On the other hand, the third magnetic working substance (11c) of the second magnetic refrigerator (M2) has a relatively large magnetocaloric effect, and thus, can sufficiently cool the heating medium. As a result, the temperature of the heating medium flowing through the second magnetic refrigerator (M2) can be kept from deviating from the operating temperature range of the second magnetic refrigerator (M2).

Further, this configuration can keep the temperature of the heating medium from deviating from the operating temperature range of the magnetic refrigerator (M) in spite of the temperature change of the heating medium flowing through a certain magnetic refrigerator (M) caused by the switching from the bypass action to the normal action.

Specific examples of how the maximum value of the magnetocaloric effect of the endmost magnetic working substance (11c, 11d) is made larger than the maximum value of the magnetocaloric effect of the intermediate magnetic working substance (11b, 11e) in each magnetic refrigerator (M) are described below.

Amount of Change in Magnetic Flux Density

The amount of change in magnetic flux density of the endmost magnetic working substance (11c, 11d) is made larger than the amount of change in magnetic flux density of the intermediate magnetic working substance (11b, 11e). This can make the maximum value of the magnetocaloric effect of the endmost magnetic working substance (11c, 11d) greater than the maximum value of the magnetocaloric effect of the intermediate magnetic working substance (11b, 11e).

Adiabatic Temperature Change ΔTad of Magnetic Working Substance

An adiabatic temperature change ΔTad of the endmost magnetic working substance (11c, 11d) is made larger than an adiabatic temperature change ΔTad of the intermediate magnetic working substance (11b, 11e). This can make the maximum value of the magnetocaloric effect of the endmost magnetic working substance (11c, 11d) greater than the maximum value of the magnetocaloric effect of the intermediate magnetic working substance (11b, 11e).

Entropy Change ΔSm of Magnetic Working Substance

An entropy change ΔSm of the endmost magnetic working substance (11c, 11d) is made larger than an entropy change ΔSm of the intermediate magnetic working substance (11b, 11e). This can make the maximum value of the magnetocaloric effect of the endmost magnetic working substance (11c, 11d) greater than the maximum value of the magnetocaloric effect of the intermediate magnetic working substance (11b, 11e).

Weight of Magnetic Working Substance

The endmost magnetic working substance (11c, 11d) is provided with a higher weight than the intermediate magnetic working substance (11b, 11e). This can make the maximum value of the magnetocaloric effect of the endmost magnetic working substance (11c, 11d) greater than the maximum value of the magnetocaloric effect of the intermediate magnetic working substance (11b, 11e).

Examples of how the weight of the endmost magnetic working substance (11c, 11d) is made higher than the weight of the intermediate magnetic working substance (lib, lie) are described below.

1) Filling Factor of Magnetic Working Substance

The filling factor of the endmost magnetic working substance (11c, 11d) in the bed (10) is made higher than the filling factor of the intermediate magnetic working substance (11b, 11e) in the bed (10). This can make the weight of the endmost magnetic working substance (11c, 11d) higher than the weight of the intermediate magnetic working substance (11b, 11e).

2) Volume of Magnetic Working Substance

The volume of the endmost magnetic working substance (11c, 11d) in the bed (10) is made higher than the volume of the intermediate magnetic working substance (11b, 11e) in the bed (10). This can make the weight of the endmost magnetic working substance (11c, 11d) higher than the weight of the intermediate magnetic working substance (11b, 11e). The volume mentioned herein is strictly a “bulk volume” including voids formed in the magnetic working substance (11).

Third Embodiment

A magnetic refrigeration apparatus (1) shown in FIG. 12 includes two thermal storage sections (81, 82). The two thermal storage sections (81, 82) include a first thermal storage section (81) connected to the first channel (40) and a second thermal storage section (82) connected to the second channel (50). Each thermal storage section (81, 82) is comprised of a reservoir (thermal storage container) for storing the heating medium.

The first thermal storage section (81) is provided in the first intermediate path (42) of the first channel (40). The first thermal storage section (81) is provided in the first intermediate path (42) between the outlet end of the first bypass channel (63) and the inlet end of the second bypass channel (65). The first thermal storage section (81) stores heat of the heating medium having flowed through the first bypass channel (63). The second thermal storage section (82) is provided in the second intermediate path (52) of the second channel (50). The second thermal storage section (82) is provided in the second intermediate path (52) between the outlet end of the third bypass channel (67) and the inlet end of the fourth bypass channel (69).

The thermal storage sections (81, 82) provided in this manner can keep the temperature of the heating medium flowing through the magnetic refrigerator (M) from deviating from the operating temperature range of the magnetic refrigerator (M) during the bypass action.

When the normal heating action is switched to the first bypass heating action, a relatively low-temperature heating medium flows through the second intermediate path (52) via the third bypass channel (67). The heating medium in the second intermediate path (52) flows into the second thermal storage section (82).

The second thermal storage section (82) contains the heating medium heated in the second magnetic refrigerator (M2) in the last normal heating action. This raises the temperature of the heating medium that has flowed into the second thermal storage section (82) via the third bypass channel (67). Thus, the temperature of the heating medium flowing through the first magnetic refrigerator (M1) is higher than the temperature of the heating medium flowing through the second bypass channel (65). This can keep the temperature of the heating medium flowing through the first magnetic refrigerator (M1) from deviating from the operating temperature range of the first magnetic refrigerator (M1).

When the normal cooling action is switched to the first bypass cooling action, a relatively high-temperature heating medium flows through the first intermediate path (42) via the first bypass channel (63). The heating medium in the first intermediate path (42) flows into the first thermal storage section (81).

The first thermal storage section (81) contains the heating medium cooled in the first magnetic refrigerator (M1) in the last normal cooling action. This lowers the temperature of the heating medium that has flowed into the first thermal storage section (81) via the first bypass channel (63). Thus, the temperature of the heating medium flowing through the second magnetic refrigerator (M2) is lower than the temperature of the heating medium flowing through the first bypass channel (63). This can keep the temperature of the heating medium flowing through the second magnetic refrigerator (M2) from deviating from the operating temperature range of the second magnetic refrigerator (M2).

Further, this configuration can keep the temperature of the heating medium from deviating from the operating temperature range of the magnetic refrigerator (M) in spite of the temperature change of the heating medium flowing through a certain magnetic refrigerator (M) caused by the switching from the bypass action to the normal action.

First Variation of Third Embodiment

A magnetic refrigeration apparatus (1) according to a first variation of the third embodiment shown in FIG. 13 has the thermal storage sections (81, 82) and the peripheral components configured differently from those of the magnetic refrigeration apparatus (1) of the third embodiment.

The heating medium circuit (C) includes a first three-way valve (91), a second three-way valve (92), a third three-way valve (93), and a fourth three-way valve (94) connected thereto. Each of the three-way valves (91, 92, 93, 94) has three ports. Each of the three ports is configured to be openable and closable.

The first upstream portion (63a), the first downstream portion (63b), and a first thermal storage channel (75) are connected to the first three-way valve (91). The second upstream portion (65a), the second downstream portion (65b), and the first thermal storage channel (75) are connected to the second three-way valve (92). The third upstream portion (67a), the third downstream portion (67b), and a second thermal storage channel (76) are connected to the third three-way valve (93). The fourth upstream portion (69a), the fourth downstream portion (69b), and the second thermal storage channel (76) are connected to the fourth three-way valve (94).

In the normal heating action, the third three-way valve (93) closes the port to the third upstream portion (67a) and the port to the third downstream portion (67b). The fourth three-way valve (94) closes the port to the fourth upstream portion (69a). The heating medium in the second channel (50) flows through the second magnetic refrigerator (M2) and the first magnetic refrigerator (M1) in this order. This heating medium does not flow through the second thermal storage section (82). Thus, at the start of the normal heating action, for example, this configuration can keep the thermal capacity of the second thermal storage section (82) from affecting smooth increase in the heat dissipation capacity of the second heat exchanger (32).

In the first bypass heating action, the third three-way valve (93) opens the port to the third upstream portion (67a) and the port to the second thermal storage channel (76), and closes the port to the third downstream portion (67b). The fourth three-way valve (94) opens the port to the second thermal storage channel (76) and the port to the fourth upstream portion (69a), and closes the port to the fourth downstream portion (69b). The relatively low-temperature heating medium in the second channel (50) flows through the third upstream portion (67a), the second thermal storage section (82) of the second thermal storage channel (76), and the fourth upstream portion (69a) in this order, and then flows through the first magnetic refrigerator (M1). The temperature of the heating medium flowing through the first magnetic refrigerator (M1) can be kept from suddenly dropping due to the effect of the thermal capacity of the second thermal storage section (82). This can keep the temperature of the heating medium flowing through the first magnetic refrigerator (M1) from deviating from the operating temperature range of the first magnetic refrigerator (M1).

In the normal cooling action, the first three-way valve (91) closes the port to the first upstream portion (63a) and the port to the first downstream portion (63b). The second three-way valve (92) closes the port to the second upstream portion (65a). The heating medium in the first channel (40) flows through the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) in this order. This heating medium does not flow through the first thermal storage section (81). Thus, at the start of the normal cooling action, for example, this configuration can keep the thermal capacity of the first thermal storage section (81) from affecting smooth increase in the cooling capacity of the first heat exchanger (31).

In the first bypass cooling action, the first three-way valve (91) opens the port to the first upstream portion (63a) and the port to the first thermal storage channel (75), and closes the port to the first downstream portion (63b). The second three-way valve (92) opens the port to the first thermal storage channel (75) and the port to the second upstream portion (65a), and closes the port to the second downstream portion (65b). The relatively high-temperature heating medium in the first channel (40) flows through the first upstream portion (63a), the first thermal storage section (81) of the first thermal storage channel (75), and the second upstream portion (65a) in this order, and then flows through the second magnetic refrigerator (M2). The temperature of the heating medium flowing through the second magnetic refrigerator (M2) can be kept from suddenly increasing due to the effect of the thermal capacity of the first thermal storage section (81). This can keep the temperature of the heating medium flowing through the second magnetic refrigerator (M2) from deviating from the operating temperature range of the second magnetic refrigerator (M2).

Further, this configuration can keep the temperature of the heating medium from deviating from the operating temperature range of the magnetic refrigerator (M) in spite of the temperature change of the heating medium flowing through a certain magnetic refrigerator (M) caused by the switching from the bypass action to the normal action.

Second Variation of Third Embodiment

A magnetic refrigeration apparatus (1) according to a second variation of the third embodiment shown in FIG. 14 has the thermal storage sections and the peripheral components configured differently from those of the magnetic refrigeration apparatus (1) of the third embodiment.

The first magnetic refrigerator (M1) is provided with a first thermal storage unit (83) and a second thermal storage unit (84). The first thermal storage unit (83) and the second thermal storage unit (84) are configured as reservoirs. The first thermal storage unit (83) is provided at an inlet of the first magnetic refrigerator (M1) connected to the first channel (40). The second thermal storage unit (84) is provided at an inlet of the first magnetic refrigerator (M1) connected to the second channel (50).

The second magnetic refrigerator (M2) is provided with a third thermal storage unit (85) and a fourth thermal storage unit (86). The third thermal storage unit (85) and the fourth thermal storage unit (86) are configured as reservoirs. The third thermal storage unit (85) is provided at an inlet of the second magnetic refrigerator (M2) connected to the first channel (40). The fourth thermal storage unit (86) is provided at an inlet of the second magnetic refrigerator (M2) connected to the second channel (50).

The second thermal storage unit (84) and the third thermal storage unit (85) correspond to the thermal storage sections. Note that the first thermal storage unit (83) and the fourth thermal storage unit (86) may be omitted.

When the normal heating action is switched to the first bypass heating action, a relatively low-temperature heating medium flows through the second intermediate path (52) via the third bypass channel (67). The heating medium in the second intermediate path (52) passes through the second thermal storage unit (84), and then flows through the first magnetic refrigerator (M1). Thus, the temperature of the heating medium flowing through the first magnetic refrigerator (M1) can be kept from deviating from the operating temperature range of the first magnetic refrigerator (M1).

When the normal cooling action is switched to the first bypass cooling action, a relatively high-temperature heating medium flows through the first intermediate path (42) via the first bypass channel (63). The heating medium in the first intermediate path (42) passes through the third thermal storage unit (85), and then flows through the second magnetic refrigerator (M2). Thus, the temperature of the heating medium flowing through the second magnetic refrigerator (M2) can be kept from deviating from the operating temperature range of the second magnetic refrigerator (M2).

Further, this configuration can keep the temperature of the heating medium from deviating from the operating temperature range of the magnetic refrigerator (M) in spite of the temperature change of the heating medium flowing through a certain magnetic refrigerator (M) caused by the switching from the bypass action to the normal action (in which the heating medium flows through the magnetic refrigerator (M)).

The thermal storage section according to the third embodiment and the variations described above may be a thermal storage material. The thermal storage material is made of a metal material having a large thermal capacity or a phase change material. A channel through which the heating medium flows is formed in the thermal storage material. Heat is exchanged between the heating medium flowing through the channel and the thermal storage material.

The thermal storage section may be a thermal storage unit including the thermal storage material provided in a reservoir storing the heating medium.

Fourth Embodiment

A magnetic refrigeration apparatus (1) of a fourth embodiment switches between a cooling operation and a heating operation. As illustrated in FIG. 15, the heating medium circuit (C) of the magnetic refrigeration apparatus (1) includes an indoor heat exchanger (33), an outdoor heat exchanger (34), a first four-way switching valve (35), and a second four-way switching valve (36). The indoor heat exchanger (33) is placed inside. The outdoor heat exchanger (34) is placed outside.

Each of the first and second four-way switching valves (35) and (36) has four ports (P1, P2, P3, P4). The first port (P1) of the first four-way switching valve (35) is connected to the first conveying channel (61) through a first relay path (71). The second port (P2) of the first four-way switching valve (35) is connected to one end of the outdoor heat exchanger (34). The third port (P3) of the first four-way switching valve (35) is connected to the second conveying channel (62) through a second relay path (72). The fourth port (P4) of the first four-way switching valve (35) is connected to one end of the indoor heat exchanger (33). The outlet end of the second conveying channel (62) is connected to the first upstream path (41).

The first port (P1) of the second four-way switching valve (36) is connected to the first downstream path (43) of the first channel (40). The second port (P2) of the second four-way switching valve (36) is connected to the other end of the outdoor heat exchanger (34). The third port (P3) of the second four-way switching valve (36) is connected to the second downstream path (53) of the second channel (50) through a third relay path (73). The fourth port (P4) of the second four-way switching valve (36) is connected to the other end of the indoor heat exchanger (33).

Each of the first four-way switching valve (35) and the second four-way switching valve (36) switches between a first state (a state indicated by solid curves in FIG. 15) and a second state (a state indicated by broken curves in FIG. 16). Each of the four-way switching valves (35, 36) in the first state makes the first port (P1) and the second port (P2) communicate with each other, and the third port (P3) and the fourth port (P4) communicate with each other. Each of the four-way switching valves (35, 36) in the second state makes the first port (P1) and the fourth port (P4) communicate with each other, and the second port (P2) and the third port (P3) communicate with each other.

Operation

The operation of the magnetic refrigeration apparatus (1) will be described below. Cooling Operation

In the cooling operation, the first four-way switching valve (35) and the second four-way switching valve (36) are in the second state. In the cooling operation, the first and second actions are alternately repeated.

In the first action shown in FIG. 16, each of the magnetic field modulators (12) of the first and second magnetic refrigerators (M1) and (M2) performs the first modulation action. The conveying mechanism (20) performs the first conveying action. In the first action, normally, the controller (100) closes the first control valve (64), the second control valve (66), the third control valve (68), and the fourth control valve (70).

In the first action, the heating medium heated by each of the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) in the second channel (50) is supplied to the outdoor heat exchanger (34) corresponding to the second heat exchange section. The heating medium dissipates heat to the outdoor air in the outdoor heat exchanger (34).

When the third control valve (68) is open in the first action, a bypass action is performed in which the heating medium bypasses the second magnetic refrigerator (M2) and is heated in the first magnetic refrigerator (M1). When the fourth control valve (70) is open in the first action, a bypass action is performed in which the heating medium is heated in the second magnetic refrigerator (M2) and bypasses the first magnetic refrigerator (M1).

In the second action shown in FIG. 17, each of the magnetic field modulators (12) of the first and second magnetic refrigerators (M1) and (M2) performs the second modulation action. The conveying mechanism (20) performs the second conveying action. In the second action, normally, the controller (100) closes the first control valve (64), the second control valve (66), the third control valve (68), and the fourth control valve (70).

In the second action, the heating medium cooled by each of the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) in the first channel (40) is supplied to the indoor heat exchanger (33) corresponding to the first heat exchange section. The indoor air is cooled by the heating medium in the indoor heat exchanger (33).

When the first control valve (64) is open in the second action, a bypass action is performed in which the heating medium bypasses the first magnetic refrigerator (M1) and is cooled in the second magnetic refrigerator (M2). When the second control valve (66) is open in the second action, a bypass action is performed in which the heating medium is cooled in the first magnetic refrigerator (M1) and bypasses the second magnetic refrigerator (M2).

Heating Operation

In the heating operation, the first four-way switching valve (35) and the second four-way switching valve (36) are in the first state. In the heating operation, the third and fourth actions are alternately and repeatedly performed.

In the third action shown in FIG. 18, each of the magnetic field modulators (12) of the first and second magnetic refrigerators (M1) and (M2) performs the first modulation action. The conveying mechanism (20) performs the first conveying action. In the third action, normally, the controller (100) closes the first control valve (64), the second control valve (66), the third control valve (68), and the fourth control valve (70).

In the third action, the heating medium heated by each of the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) in the second channel (50) is supplied to the indoor heat exchanger (33) corresponding to the second heat exchange section. The indoor air is heated by the heating medium in the indoor heat exchanger (33).

When the third control valve (68) is open in the third action, a bypass action is performed in which the heating medium bypasses the second magnetic refrigerator (M2) and is heated in the first magnetic refrigerator (M1). When the fourth control valve (70) is open in the third action, a bypass action is performed in which the heating medium is heated in the second magnetic refrigerator (M2) and bypasses the first magnetic refrigerator (M1).

In the fourth action shown in FIG. 19, each of the magnetic field modulators (12) of the first and second magnetic refrigerators (M1) and (M2) performs the second modulation action. The conveying mechanism (20) performs the second conveying action. In the fourth action, normally, the controller (100) closes the first control valve (64), the second control valve (66), the third control valve (68), and the fourth control valve (70).

In the fourth action, the heating medium cooled by each of the first magnetic refrigerator (M1) and the second magnetic refrigerator (M2) in the first channel (40) is supplied to the outdoor heat exchanger (34) corresponding to the first heat exchange section. The heating medium absorbs heat from the outdoor air in the outdoor heat exchanger (34).

When the first control valve (64) is open in the fourth action, a bypass action is performed in which the heating medium bypasses the first magnetic refrigerator (M1) and is cooled in the second magnetic refrigerator (M2). When the second control valve (66) is open in the fourth action, a bypass action is performed in which the heating medium is cooled in the first magnetic refrigerator (M1) and bypasses the second magnetic refrigerator (M2).

Other Variations

The embodiments described above may be modified as described in the following variations within an applicable range.

$\text{Variation A-Bypass}\text{Mechanism}$

As illustrated in FIG. 20, bypass mechanisms (B) of variation A are obtained by adding control valves to the bypass mechanisms of the embodiments. The first bypass mechanism (B1) includes a fifth control valve (95). The fifth control valve (95) is provided in the first channel (40) near the inlet of the first magnetic refrigerator (M1). The second bypass mechanism (B2) includes a sixth control valve (96). The sixth control valve (96) is provided in the first channel (40) near the inlet of the second magnetic refrigerator (M2). The third bypass mechanism (B3) includes a seventh control valve (97). The seventh control valve (97) is provided in the second channel (50) near the inlet of the second magnetic refrigerator (M2). The fourth bypass mechanism (B4) includes an eighth control valve (98). The eighth control valve (98) is provided in the second channel (50) nearthe inlet of the first magnetic refrigerator (M1).

When the first bypass mechanism (B1) performs the bypass action, the first control valve (64) is opened, and the fifth control valve (95) is closed. This allows the heating medium in the first channel (40) to reliably bypass the first magnetic refrigerator (M1).

When the second bypass mechanism (B2) performs the bypass action, the second control valve (66) is opened, and the sixth control valve (96) is closed. This allows the heating medium in the first channel (40) to reliably bypass the second magnetic refrigerator (M2).

When the third bypass mechanism (B3) performs the bypass action, the third control valve (68) is opened, and the seventh control valve (97) is closed. This allows the heating medium in the second channel (50) to reliably bypass the second magnetic refrigerator (M2).

When the fourth bypass mechanism (B4) performs the bypass action, the fourth control valve (70) is opened, and the eighth control valve (98) is closed. This allows the heating medium in the second channel (50) to reliably bypass the first magnetic refrigerator (M1).

The fifth control valve (95), the sixth control valve (96), the seventh control valve (97), and the eighth control valve (98) may be on-off valves or flow regulating valves.

$\text{Variation B-Bypass}\text{Mechanism}$

As illustrated in FIG. 21, the bypass mechanisms (B) of variation B include three-way valves instead of the control valves. The first bypass mechanism (B1) includes a fifth three-way valve (55). The fifth three-way valve (55) switches between a state in which the heating medium in the first upstream path (41) is supplied only to the first magnetic refrigerator (M1) and a state in which the heating medium is supplied only to the first bypass channel (63). The second bypass mechanism (B2) includes a sixth three-way valve (56). The sixth three-way valve (56) switches between a state in which the heating medium in the first intermediate path (42) is supplied only to the second magnetic refrigerator (M2) and a state in which the heating medium is supplied only to the second bypass channel (65). The third bypass mechanism (B3) includes a seventh three-way valve (57). The seventh three-way valve (57) switches between a state in which the heating medium in the second upstream path (51) is supplied only to the second magnetic refrigerator (M2) and a state in which the heating medium is supplied only to the third bypass channel (67). The fourth bypass mechanism (B4) includes an eighth three-way valve (58). The eighth three-way valve (58) is switched between a state in which the heating medium in the second intermediate path (52) is supplied only to the first magnetic refrigerator (M1) and a state in which the heating medium is supplied only to the fourth bypass channel (69).

These three-way valves (55, 56, 57, 58) may be configured to adjust the ratio of the flow rate of the heating medium supplied to the magnetic refrigerator (M) and the flow rate of the heating medium supplied to the bypass channel (63, 65, 67, 69).

$\text{Variation C-Conveying}\text{Mechanism}$

As illustrated in FIG. 22, the conveying mechanism (20) of variation C includes a once-through pump (26) and a four-way switching valve (27) serving as a selector. The four-way switching valve (27) switches between a first state (the state indicated by solid curves in FIG. 22) and a second state (the state indicated by broken curves in FIG. 22). The four-way switching valve (27) in the first state allows a discharge portion of the pump (26) to communicate with the first conveying channel (61) and allows a suction portion of the pump (26) to communicate with the second conveying channel (62). The four-way switching valve (27) in the second state allows the discharge portion of the pump (26) to communicate with the second conveying channel (62) and allows the suction portion of the pump (26) to communicate with the first conveying channel (61).

In the first conveying action, the pump (26) is in operation, and the four-way switching valve (27) is in the first state. In the second conveying action, the pump (26) is in operation, and the four-way switching valve (27) is in the second state. The conveying mechanism (20) alternately and repeatedly performs the first conveying action and the second conveying action.

Variation D - Three or More Magnetic Refrigerators

Three or more magnetic refrigerators (M) may be connected in series to the first channel (40) and the second channel (50). In the example shown in FIG. 23, three magnetic refrigerators (M) are provided in the first channel (40) and the second channel (50). The first channel (40) has three bypass mechanisms (B) corresponding to the three magnetic refrigerators (M). The second channel (50) has three bypass mechanisms (B) corresponding to the three magnetic refrigerators (M).

$\text{Variation E-Parallel}\text{Circuit}$

As illustrated in FIG. 24, the heating medium circuit (C) of variation E includes a plurality of circuits connected in parallel. The circuits include a first circuit (C1) and a second circuit (C2). Three or more circuits may be connected in parallel in the heating medium circuit (C). The first circuit (C1) includes a first channel (40), a second channel (50), a plurality of magnetic refrigerators (M), and a plurality of bypass mechanisms (B), similarly to the heating medium circuit of the above-described embodiments. Likewise, the second circuit (C2) includes a first channel (40), a second channel (50), a plurality of magnetic refrigerators (M), and a plurality of bypass mechanisms (B). A first heat exchanger (31), a second heat exchanger (32), a first conveying channel (61), and a second conveying channel (62) are connected to each of the first circuit (C1) and the second circuit (C2).

In the normal heating action, the heating medium in the first conveying channel (61) is divided to flow into the first circuit (C1) and the second circuit (C2). In each of the first circuit (C1) and the second circuit (C2), the heating medium flows through the second channel (50) and is heated by the plurality of magnetic refrigerators (M). The flows of the heating medium heated in the first circuit (C1) and the second circuit (C2) meet together and then supplied to the second heat exchanger (32).

In the normal cooling action, the heating medium in the second conveying channel (62) is divided to flow into the first circuit (C1) and the second circuit (C2). In each of the first circuit (C1) and the second circuit (C2), the heating medium flows through the first channel (40) and is cooled by the plurality of magnetic refrigerators (M). The flows of the heating medium cooled in the first circuit (C1) and the second circuit (C2) meet together and then supplied to the first heat exchanger (31).

In the heating action and the cooling action, the bypass action is appropriately performed as a result of the switching by the bypass mechanisms (B).

$\text{Variation F}-\text{Single-Layer Magnetic Refrigerator}$

As illustrated in FIG. 25, the magnetic refrigerator (M) may be a single-layer magnetic refrigerator having one magnetic working substance (11).

Two or more magnetic refrigerators (M) are connected in series in the first channel (40) and the second channel (50) with the magnetic working substances (11) of the magnetic refrigerators (M) being arranged in an ascending order of the Curie temperature. This can increase the magnetocaloric effect of the magnetic refrigerators (M).

The magnetic working substances (11) of an adjacent pair of the magnetic refrigerators (M) have the operating temperature ranges partially overlapping each other. Thus, the temperature of the heating medium can be kept from deviating from the operating temperature range of the magnetic working substance (11) in spite of the temperature change of the heating medium flowing into the magnetic refrigerator (M) caused by the switching of the bypass action.

Specifically, the maximum value of the magnetocaloric effect in the overlapping area of the operating temperature ranges is equal to or more than ½ of the average value of the maximum values of the magnetocaloric effect of the magnetic working substances (11) of the adjacent magnetic refrigerators (M). This makes the operating temperature ranges of the adjacent magnetic refrigerators overlap in a wider area. This can reliably keep the temperature of the heating medium from deviating from the operating temperature range of the magnetic working substance (11) when the normal action is switched to the bypass action and the bypass action is switched to the normal action.

Fifth Embodiment

As illustrated in FIG. 26, a magnetic refrigeration apparatus (1) of the fifth embodiment is an air conditioner that switches between cooling and heating.

The magnetic refrigeration apparatus (1) includes an indoor fan (14) and an outdoor fan (15). The indoor fan (14) is disposed near the indoor heat exchanger (33). The indoor fan (14) transports indoor air passing through the indoor heat exchanger (33). The outdoor fan (15) is disposed near the outdoor heat exchanger (34). The outdoor fan (15) transports outdoor air passing through the outdoor heat exchanger (34).

The heating medium circuit (C) has a plurality of magnetic refrigerators (M). The magnetic refrigerators (M) include a low-temperature magnetic refrigerator (ML), a medium-temperature magnetic refrigerator (MM), and a high-temperature magnetic refrigerator (MH). The low-temperature magnetic refrigerator (ML) and the high-temperature magnetic refrigerator (MH) constitute third magnetic refrigerators. The medium-temperature magnetic refrigerator (MM) constitutes a fourth magnetic refrigerator. The magnetic refrigerators (M) are connected in series in the heating medium circuit (C) to extend over the first channel (40) and the second channel (50).

The heating medium circuit (C) has a third four-way switching valve (37) and a fourth four-way switching valve (38). Each of the third and fourth four-way switching valves (37) and (38) has a first port (P1), a second port (P2), a third port (P3), and a fourth port (P4). The third and fourth four-way switching valves (37) and (38) can switch between a first state indicated by solid curves in FIG. 26 and a second state indicated by broken curves in FIG. 26. Each of the third and fourth four-way switching valves (37) and (38) in the first state makes the first port (P1) and the second port (P2) communicate with each other, and simultaneously makes the third port (P3) and the fourth port (P4) communicate with each other. Each of the third and fourth four-way switching valves (37) and (38) in the second state makes the first port (P1) and the fourth port (P4) communicate with each other, and simultaneously makes the second port (P2) and the third port (P3) communicate with each other.

The first port (P1) of the third four-way switching valve (37) communicates with an outlet end of the second channel (50). The second port (P2) of the third four-way switching valve (37) communicates with one end of the outdoor heat exchanger (34). The third port (P3) of the third four-way switching valve (37) communicates with an inlet end of the second channel (50). The fourth port (P4) of the third four-way switching valve (37) communicates with one end of the indoor heat exchanger (33).

The first port (P1) of the fourth four-way switching valve (38) communicates with an inlet end of the first channel (40). The second port (P2) of the fourth four-way switching valve (38) communicates with the other end of the outdoor heat exchanger (34). The third port (P3) of the fourth four-way switching valve (38) communicates with an outlet end of the first channel (40). The fourth port (P4) of the fourth four-way switching valve (38) communicates with the other end of the indoor heat exchanger (33).

The first channel (40) has a fifth bypass mechanism (B5) provided for each of the magnetic refrigerators (M). The second channel (50) has a sixth bypass mechanism (B6) provided for each of the magnetic refrigerators (M). Each of the fifth bypass mechanisms (B5) and the sixth bypass mechanisms (B6) includes a bypass channel (60) and a valve (a control valve (90)) for opening and closing the bypass channel (60).

Operation

The operation of the magnetic refrigeration apparatus (1) of the fifth embodiment will be described below.

Cooling Operation

In the cooling operation, the third four-way switching valve (37) and the fourth four-way switching valve (38) are in the first state. The outdoor fan (15) and the indoor fan (14) are operated. In the cooling operation, the first and second actions are alternately repeated. As an example, a cooling operation in which all the magnetic refrigerators (M) are in operation will be described below.

In the first action shown in FIG. 27, the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) perform the first modulation action. The conveying mechanism (20) performs the first conveying action. All the control valves (90) are closed.

In the first action, the heating medium heated by the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) in the second channel (50) is supplied to the outdoor heat exchanger (34). The heating medium dissipates heat to the outdoor air in the outdoor heat exchanger (34).

In the second action shown in FIG. 28, the high-temperature magnetic refrigerator (MH), the medium-temperature magnetic refrigerator (MM), and the low-temperature magnetic refrigerator (ML) perform the second modulation action. The conveying mechanism (20) performs the second conveying action. All the control valves (90) are closed.

In the second action, the heating medium cooled by the high-temperature magnetic refrigerator (MH), the medium-temperature magnetic refrigerator (MM), and the low-temperature magnetic refrigerator (ML) in the first channel (40) is supplied to the indoor heat exchanger (33). The indoor air is cooled by the heating medium in the indoor heat exchanger (33).

Heating Operation

In the heating operation, the third four-way switching valve (37) and the fourth four-way switching valve (38) are in the second state. The outdoor fan (15) and the indoor fan (14) are operated. In the heating operation, the third and fourth actions are alternately and repeatedly performed. As an example, a heating operation in which all the magnetic refrigerators (M) are in operation will be described below.

In the third action shown in FIG. 29, the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) perform the first modulation action. The conveying mechanism (20) performs the first conveying action. All the control valves (90) are closed.

In the third action, the heating medium heated by the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) in the second channel (50) is supplied to the indoor heat exchanger (33). The heating medium dissipates heat to the indoor air in the indoor heat exchanger (33).

In the fourth action shown in FIG. 30, the high-temperature magnetic refrigerator (MH), the medium-temperature magnetic refrigerator (MM), and the low-temperature magnetic refrigerator (ML) perform the second modulation action. The conveying mechanism (20) performs the second conveying action. All the control valves (90) are closed.

In the fourth action, the heating medium cooled by the high-temperature magnetic refrigerator (MH), the medium-temperature magnetic refrigerator (MM), and the low-temperature magnetic refrigerator (ML) in the first channel (40) is supplied to the outdoor heat exchanger (34). The heating medium absorbs heat from the outdoor air in the outdoor heat exchanger (34).

Properties of Magnetic Refrigerator

In the magnetic refrigeration apparatus (1) of this embodiment, the magnetic refrigerators (M) are configured in consideration of the operating conditions for the cooling operation and the heating operation. Detailed description will be made below with reference to FIG. 31.

1) Temperature Range

In the cooling operation of the magnetic refrigeration apparatus (1), the minimum and maximum temperatures of the heating medium are determined depending on the outdoor temperature and the cooling load. During the cooling operation under rated conditions, the minimum temperature is T1min, and the maximum temperature is T1max. The minimum temperature T1min is based on the indoor temperature and the set temperature during the cooling operation under the rated conditions. The maximum temperature T1max is based on the outdoor temperature during the cooling operation under the rated conditions.

In the cooling operation, the minimum temperature is T2min and the maximum temperature is T2max in the maximum range wider than the range under the rated conditions. The minimum temperature T2min is a temperature of the heating medium when the cooling load is extremely high. The maximum temperature T2max is a temperature of the heating medium when the outdoor temperature is extremely high.

In the heating operation of the magnetic refrigeration apparatus (1), the minimum temperature and the maximum temperature of the heating medium are determined depending on the outdoor temperature and the heating load. During the heating operation under rated conditions, the minimum temperature is T3min, and the maximum temperature is T3max. The minimum temperature T3min is based on the outdoor temperature during the heating operation under the rated conditions. The maximum temperature T3max is based on the indoor temperature and the set temperature during the heating operation under the rated conditions.

In the heating operation, the minimum temperature is T4min and the maximum temperature is T4max in the maximum range wider than the range under the rated conditions. The minimum temperature T4min is a temperature of the heating medium when the outdoor temperature is extremely low. The maximum temperature T4max is a temperature of the heating medium when the heating load is extremely high. In this embodiment, the maximum temperature T4max and the maximum temperature T2max are the same.

As illustrated in FIG. 31, three temperature ranges of the heating medium are determined based on the frequency with which the temperature of the heating medium in the heating medium circuit (C) falls within the range. The first temperature range is a range from the minimum temperature T4min to the minimum temperature T3min. The second temperature range is a range from the minimum temperature T3min to the maximum temperature T1max. The third temperature range is a range from the maximum temperature T1max to the maximum temperature T2max (T4max). The second temperature range is a range from the minimum temperature (i.e., T3min) to the maximum temperature (i.e., T1max) across both the temperature range of the rated cooling operation and the temperature range of the rated heating operation. The first temperature range is a lower temperature range than the second temperature range. The third temperature range is a higher temperature range than the second temperature range.

The second temperature range is a temperature range that the temperature of the heating medium falls within more frequently taking all the operations of the magnetic refrigeration apparatus (1) into account. The first and third temperature ranges are temperature ranges that the temperature of the heating medium falls within less frequently taking all the operations of the magnetic refrigeration apparatus (1) into account.

2) Properties of Low-Temperature Magnetic Refrigerator

The low-temperature magnetic refrigerator (ML), which is the third magnetic refrigerator, is located at the end (strictly speaking, the low-temperature end) of the plurality of magnetic refrigerators (M). The low-temperature magnetic refrigerator (ML) is adjacent to the indoor heat exchanger (33) serving as a heat absorber during the cooling operation. The high-temperature magnetic refrigerator (MH) is adjacent to the outdoor heat exchanger (34) serving as a heat absorber during the heating operation.

As illustrated in FIG. 31, the low-temperature magnetic refrigerator (ML) of this example has two magnetic working substances (11) (low-temperature magnetic working substances (11L)). The whole operating temperature range of the low-temperature magnetic refrigerator (ML) includes the first temperature range. In other words, the low-temperature magnetic refrigerator (ML) is configured to exhibit the magnetocaloric effect when the temperature of the heating medium is in the first temperature range. Note that “the whole operating temperature range of the magnetic refrigerator (M)” does not mean the operating temperature range of the magnetic working substance (11) alone, but means the temperature range from the minimum temperature to the maximum temperature in which the magnetic refrigerator (M) exhibits the magnetocaloric effect.

In the heating operation under the extremely low outdoor temperature, the low temperature of the heating medium may fall within the first temperature range. The low-temperature magnetic refrigerator (ML) exhibits the magnetocaloric effect on the heating medium in the first temperature range.

3) Properties of High-Temperature Magnetic Refrigerator

The high-temperature magnetic refrigerator (MH), which is the third magnetic refrigerator, is located at the end (strictly speaking, the high-temperature end) of the plurality of magnetic refrigerators (M). The high-temperature magnetic refrigerator (MH) is adjacent to the outdoor heat exchanger (34) serving as a radiator during the cooling operation. The high-temperature magnetic refrigerator (MH) is adjacent to the indoor heat exchanger (33) serving as a radiator during the heating operation.

As illustrated in FIG. 31, the high-temperature magnetic refrigerator (MH) of this example is a single-layer magnetic refrigerator and has a single magnetic working substance (11) (a high-temperature magnetic working substance (11H)). The whole operating temperature range of the high-temperature magnetic refrigerator (MH) includes the third temperature range. In other words, the high-temperature magnetic refrigerator (MH) is configured to exhibit the magnetocaloric effect when the temperature of the heating medium is in the third temperature range.

In the cooling operation under the extremely high outdoor temperature and in the heating operation under the extremely high heating load, the high-temperature of the heating medium may fall within the third temperature range. The high-temperature magnetic refrigerator (MH) exhibits the magnetocaloric effect on the heating medium in the third temperature range.

4) Properties of Medium-Temperature Magnetic Refrigerator

The medium-temperature magnetic refrigerator (MM), which is the fourth magnetic refrigerator, is located between the magnetic refrigerators (M) at both ends. As illustrated in FIG. 31, the medium-temperature magnetic refrigerator (MM) of this example has six layers of magnetic working substances (11) (medium-temperature magnetic working substances (11m)).

The whole operating temperature range of the medium-temperature magnetic refrigerator (MH) includes the second temperature range. In other words, the medium-temperature magnetic refrigerator (MM) is configured to exhibit the magnetocaloric effect when the temperature of the heating medium is in the second temperature range.

In the rated cooling operation or the rated heating operation, the temperature of the heating medium may fall within the second temperature range. The medium-temperature magnetic refrigerator (MM) exhibits the magnetocaloric effect on the heating medium in the second temperature range.

4) How Frequently Heating Medium Falls within Temperature Range

Considering the operation of the magnetic refrigeration apparatus (1) as a whole, the temperature of the heating medium falls within the whole operating temperature range of the low-temperature magnetic refrigerator (ML) less frequently than within the whole operating temperature range of the medium-temperature magnetic refrigerator (MM). Likewise, the temperature of the heating medium falls within the whole operating temperature range of the high-temperature magnetic refrigerator (MH) less frequently than within the whole operating temperature range of the mediumtemperature magnetic refrigerator (MM).

5) Relationship Between Operating Temperature Ranges of Magnetic Working Substances

As illustrated in FIG. 31, the operating temperature range A of one low-temperature magnetic working substance (11L) of the low-temperature magnetic refrigerator (ML) is wider than the operating temperature range B of one medium-temperature magnetic working substance (11M) of the medium-temperature magnetic refrigerator (MM). This configuration can produce the magnetocaloric effect in a predetermined temperature range (the first temperature range) while reducing the number of layers of the magnetic working substance (11) in the low-temperature magnetic refrigerator (ML). In this example, the number of layers in the low-temperature magnetic refrigerator (ML) is two, i.e., which is less than the number of layers (six) in the medium-temperature magnetic refrigerator (MM). Thus, the structure of the low-temperature magnetic refrigerator (ML) can be simplified, reducing the production cost of the low-temperature magnetic refrigerator (ML).

On the other hand, if the low-temperature magnetic working substances (11) of the low-temperature magnetic refrigerator (ML) have a wider operating temperature range A and the low-temperature magnetic refrigerator (ML) has a fewer number of low-temperature magnetic working substances (11L), the magnetocaloric effect is reduced as a whole, and the efficiency tends to decrease. However, the low-temperature magnetic refrigerator (ML) corresponds to the first temperature range that the temperature of the heating medium falls within less frequently. Thus, the decrease in efficiency has little influence on the whole operation of the magnetic refrigeration apparatus (1).

As illustrated in the same graph, the operating temperature range C of one high-temperature magnetic working substance (11) of the high-temperature magnetic refrigerator (MH) is wider than the operating temperature range B of one medium-temperature magnetic working substance (11) of the medium-temperature magnetic refrigerator (MM). In this example, the operating temperature range C of the high-temperature magnetic working substance (11H) is approximately as wide as the operating temperature range A of the low-temperature magnetic working substance (11L). This configuration can produce the magnetocaloric effect in a predetermined temperature range (the third temperature range) while reducing the number of layers of the magnetic working substance (11) in the high-temperature magnetic refrigerator (MH). In this example, the number of layers in the high-temperature magnetic refrigerator (MH) is one, i.e., which is less than the number of layers (two) in the medium-temperature magnetic refrigerator (MM). Thus, the structure of the high-temperature magnetic refrigerator (MH) can be simplified, reducing the production cost of the high-temperature magnetic refrigerator (MH).

On the other hand, if the high-temperature magnetic working substance (11H) of the high-temperature magnetic refrigerator (MH) has a wider operating temperature range C and the high-temperature magnetic refrigerator (MH) has a fewer number of low-temperature magnetic working substances (11), the magnetocaloric effect is reduced as a whole, and the efficiency tends to decrease. However, the high temperature magnetic refrigerator (MH) operates only in the third temperature range that the temperature of the heating medium falls within less frequently. Thus, the decrease in efficiency has little influence on the whole operation of the magnetic refrigeration apparatus (1).

6) Relationship Between Amounts of Magnetic Working Substances

The low-temperature magnetic refrigerator (ML) has a larger amount of magnetic working substance (11) than the medium-temperature magnetic refrigerator (MM). Strictly speaking, the amount of each of the low-temperature magnetic working substances (11L) is larger than the amount of each of the medium-temperature magnetic working substances (11M). As described above, the low-temperature magnetic refrigerator (ML) has fewer layers, and the magnetocaloric effect tends to decrease. However, increasing the amount of the magnetic working substance (11) in the low-temperature magnetic refrigerator (ML) can improve the heating capacity (heat dissipation capacity) and the cooling capacity (heat absorption capacity) of the low-temperature magnetic refrigerator (ML).

The high-temperature magnetic refrigerator (MH) has a larger amount of magnetic working substance (11) than the medium-temperature magnetic refrigerator (MM). Strictly speaking, the amount of the high-temperature magnetic working substance (11H) is larger than the amount of each of the medium-temperature magnetic working substances (11M). As described above, the high-temperature magnetic refrigerator (MH) has a single layer, and the magnetocaloric effect tends to decrease. However, increasing the amount of the magnetic working substance (11) in the high-temperature magnetic refrigerator (MH) can improve the heating capacity (heat dissipation capacity) and the cooling capacity (heat absorption capacity) of the high-temperature magnetic refrigerator (MH).

(1 Bypass Action

In this embodiment, the controller (100) performs an action of making the heating medium bypass the third magnetic refrigerator (ML, MH) depending on the operating conditions.

7-1) Rated Heating Operation and Rated Cooling Operation

During the rated heating operation and the rated cooling operation, the controller (100) causes the low-temperature magnetic refrigerator (ML) and the high-temperature magnetic refrigerator (MH) to perform neither the first modulation action nor the second modulation action, and causes only the medium-temperature magnetic refrigerator (MM) to perform the first modulation action and the second modulation action. In these operations, the temperature of the heating medium does not fall within the first and third temperature ranges, and it is not necessary to operate the low-temperature magnetic refrigerator (ML) and the high-temperature magnetic refrigerator (MH).

In addition, during the rated heating operation and the rated cooling operation, the controller (100) performs a bypass action, i.e., allows the heating medium to bypass the low-temperature magnetic refrigerator (ML) and the high-temperature magnetic refrigerator (MH). Specifically, the control valves (90) of the bypass channels (60) corresponding to the low-temperature magnetic refrigerator (ML) and the high-temperature magnetic refrigerator (MH) are opened, and the control valve (90) of the bypass channel (60) corresponding to the medium-temperature magnetic refrigerator (MM) is closed. Thus, the heating medium flows only through the medium-temperature magnetic refrigerator (MM) which is in operation. This configuration can reduce the increase in pressure loss caused by the heating medium flowing through the low-temperature magnetic refrigerator (ML) and the high-temperature magnetic refrigerator (MH).

A first condition for the rated heating operation or the rated cooling operation can be determined based on at least one of the outdoor temperature, the indoor temperature, or the temperature of the heating medium. When the first condition indicating the rated heating or cooling operation is met, the controller (100) operates only the medium-temperature magnetic refrigerator (MM) which is the fourth magnetic refrigerator. When the first condition is met, the controller (100) allows the heating medium to bypass the low-temperature magnetic refrigerator (ML) and the high-temperature magnetic refrigerator and flow through the medium-temperature magnetic refrigerator (MM).

7-2) Heating Operation Involving First Temperature Range

In the heating operation under the extremely low outdoor temperature, a second condition in which the low-temperature heating medium falls within the first temperature range is met. In this case, the controller (100) causes the high-temperature magnetic refrigerator (MH) to perform neither the first modulation action nor the second modulation action, and causes the low-temperature magnetic refrigerator (ML) and the medium-temperature magnetic refrigerator (MM) to perform the first modulation action and the second modulation action.

In addition, during this operation, the controller (100) performs a bypass action, i.e., allows the heating medium to bypass the high-temperature magnetic refrigerator (MH). Specifically, the control valve (90) of the bypass channel (60) corresponding to the high-temperature magnetic refrigerator (MH) is opened, and the control valves (90) of the bypass channels (60) corresponding to the low-temperature magnetic refrigerator (ML) and the medium-temperature magnetic refrigerator (MM) are closed. Thus, the heating medium flows through the low-temperature magnetic refrigerator (ML) and the medium-temperature magnetic refrigerator (MM) which are in operation. This configuration can reduce the increase in pressure loss caused by the heating medium flowing through the high-temperature magnetic refrigerator (MH).

The second condition in which the low-temperature heating medium falls within the first temperature range can be determined based on at least one of the outdoor temperature or the temperature of the heating medium. When the second condition is met, the controller (100) operates the low-temperature magnetic refrigerator (ML) and the medium-temperature magnetic refrigerator (MM). When the second condition is met, the controller (100) allows the heating medium to bypass the high-temperature magnetic refrigerator (MH) and flow through the low-temperature magnetic refrigerator (ML) and the medium-temperature magnetic refrigerator (MM).

7-3) Cooling Operation and Heating Operation involving Third Temperature Range

In the cooling operation under the extremely high outdoor temperature and in the heating operation under the extremely high heating load, a third condition in which the high-temperature heating medium falls within the third temperature range is met. In this case, the controller (100) causes the low-temperature magnetic refrigerator (ML) to perform neither the first modulation action nor the second modulation action, and causes the medium-temperature magnetic refrigerator (MM) and the high-temperature magnetic refrigerator (MH) to perform the first modulation action and the second modulation action.

In addition, during this operation, the controller (100) performs a bypass action, i.e., allows the heating medium to bypass the low-temperature magnetic refrigerator (ML). Specifically, the control valve (90) of the bypass channel (60) corresponding to the low-temperature magnetic refrigerator (ML) is opened, and the control valves (90) of the bypass channels (60) corresponding to the medium-temperature magnetic refrigerator (MM) and the high-temperature magnetic refrigerator (MH) are closed. Thus, the heating medium flows through the medium-temperature magnetic refrigerator (MM) and the high-temperature magnetic refrigerator (MH) which are in operation. This configuration can reduce the increase in pressure loss caused by the heating medium flowing through the low-temperature magnetic refrigerator (ML).

The third condition in which the high-temperature heating medium falls within the third temperature range can be determined based on at least one of the outdoor temperature, the indoor temperature, or the temperature of the heating medium. When the third condition is met, the controller (100) operates the medium-temperature magnetic refrigerator (MM) and the high-temperature magnetic refrigerator (MH). When the third condition is met, the controller (100) allows the heating medium to bypass the low-temperature magnetic refrigerator (ML) and flow through the medium-temperature magnetic refrigerator (MM) and the high-temperature magnetic refrigerator (MH).

Sixth Embodiment

As illustrated in FIG. 32, a heating medium circuit (C) of the sixth embodiment has two units (U1, U2) including the first channel (40) and the second channel (50) of the fifth embodiment. The two units (U1, U2) are comprised of a first unit (U1) and a second unit (U2) connected in parallel. These units (U1, U2) have the same configuration. Each of the units (U1, U2) includes a first channel (40), a second channel (50), a low-temperature magnetic refrigerator (ML), a medium-temperature magnetic refrigerator (MM), a high-temperature magnetic refrigerator (MH), check valves (CV), a fifth bypass mechanism (B5), and a sixth bypass mechanism (B6), similarly to the heating medium circuit of the fifth embodiment.

The sixth embodiment is different from the fifth embodiment in the configuration of the conveying mechanism (20). The conveying mechanism (20) of the sixth embodiment includes a once-through pump (26), a ninth three-way valve (28), and a tenth three-way valve (29). The pump (26) conveys the heating medium in only one direction. The pump (26) is connected to a channel between the second port (P2) of the third four-way switching valve (37) and the outdoor heat exchanger (34). The pump (26) discharges the heating medium toward the outdoor heat exchanger (34).

Each of the ninth three-way valve (28) and the tenth three-way valve (29) has first to third ports. The ninth and tenth three-way valves (28) and (29) switch between a first state indicated by solid curves in FIG. 32 and a second state indicated by broken curves in FIG. 32. Each of the ninth and tenth three-way valves (28) and (29) in the first state makes the first and third ports communicate with each other. Each of the ninth and tenth three-way valves (28) and (29) in the second state makes the first and second ports communicate with each other.

The first port of the ninth three-way valve (28) communicates with the first port (P1) of the third four-way switching valve (37). The second port of the ninth three-way valve (28) communicates with an outlet end of the second channel (50) of the first unit (U1). The third port of the ninth three-way valve (28) communicates with an outlet end of the second channel (50) of the second unit (U2).

The first port of the tenth three-way valve (29) communicates with the first port (P1) of the fourth four-way switching valve (38). The second port of the tenth three-way valve (29) communicates with an inlet end of the first channel (40) of the first unit (U1). The third port of the tenth three-way valve (29) communicates with an inlet end of the first channel (40) of the second unit (U2).

Operation

The operation of the magnetic refrigeration apparatus (1) of the sixth embodiment will be described below.

Cooling Operation

In the cooling operation, the third four-way switching valve (37) and the fourth four-way switching valve (38) are in the first state. The outdoor fan (15) and the indoor fan (14) are operated. In the cooling operation, the first and second actions are alternately repeated. As an example, a cooling operation in which all the magnetic refrigerators (M) are in operation will be described below.

In the first action shown in FIG. 33, the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) of the first unit (U1) perform the first modulation action. The low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) of the second unit (U2) perform the second modulation action. The pump (26) of the conveying mechanism (20) is operated. The ninth three-way valve (28) is in the second state, and the tenth three-way valve (29) is in the first state.

In the first action, the heating medium heated by the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) in this order in the second channel (50) of the first unit (U1) is supplied to the outdoor heat exchanger (34). The heating medium dissipates heat to the outdoor air in the outdoor heat exchanger (34). The heating medium cooled by the high-temperature magnetic refrigerator (MH), the medium-temperature magnetic refrigerator (MM), and the low-temperature magnetic refrigerator (ML) in this order in the first channel (40) of the second unit (U2) is supplied to the indoor heat exchanger (33). The heating medium absorbs heat from the indoor air in the indoor heat exchanger (33).

In the second action shown in FIG. 34, the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) of the second unit (U2) perform the first modulation action. The low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) of the first unit (U1) perform the second modulation action. The pump (26) of the conveying mechanism (20) is operated. The ninth three-way valve (28) is in the first state, and the tenth three-way valve (29) is in the second state.

In the second action, the heating medium heated by the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) in this order in the second channel (50) of the second unit (U2) is supplied to the outdoor heat exchanger (34). The heating medium dissipates heat to the outdoor air in the outdoor heat exchanger (34). The heating medium cooled by the high-temperature magnetic refrigerator (MH), the medium-temperature magnetic refrigerator (MM), and the low-temperature magnetic refrigerator (ML) in this order in the first channel (40) of the first unit (U1) is supplied to the indoor heat exchanger (33). The heating medium absorbs heat from the indoor air in the indoor heat exchanger (33).

Heating Operation

In the heating operation, the third four-way switching valve (37) and the fourth four-way switching valve (38) are in the second state. The outdoor fan (15) and the indoor fan (14) are operated. In the heating operation, the third and fourth actions are alternately and repeatedly performed. As an example, a heating operation in which all the magnetic refrigerators (M) are in operation will be described below.

In the third action shown in FIG. 35, the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) of the first unit (U1) perform the first modulation action. The low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) of the second unit (U2) perform the second modulation action. The pump (26) of the conveying mechanism (20) is operated. The ninth three-way valve (28) is in the second state, and the tenth three-way valve (29) is in the first state.

In the third action, the heating medium heated by the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) in this order in the second channel (50) of the first unit (U1) is supplied to the indoor heat exchanger (33). The heating medium dissipates heat to the indoor air in the indoor heat exchanger (33). The heating medium cooled by the high-temperature magnetic refrigerator (MH), the mediumtemperature magnetic refrigerator (MM), and the low-temperature magnetic refrigerator (ML) in this order in the first channel (40) of the second unit (U2) is supplied to the outdoor heat exchanger (34). The heating medium absorbs heat from the outdoor air in the outdoor heat exchanger (34).

In the fourth action shown in FIG. 36, the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) of the second unit (U2) perform the first modulation action. The low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) of the first unit (U1) perform the second modulation action. The pump (26) of the conveying mechanism (20) is operated. The ninth three-way valve (28) is in the first state, and the tenth three-way valve (29) is in the second state.

In the fourth action, the heating medium heated by the low-temperature magnetic refrigerator (ML), the medium-temperature magnetic refrigerator (MM), and the high-temperature magnetic refrigerator (MH) in this order in the second channel (50) of the second unit (U2) is supplied to the indoor heat exchanger (33). The heating medium dissipates heat to the indoor air in the indoor heat exchanger (33). The heating medium cooled by the high-temperature magnetic refrigerator (MH), the mediumtemperature magnetic refrigerator (MM), and the low-temperature magnetic refrigerator (ML) in this order in the first channel (40) of the first unit (U1) is supplied to the outdoor heat exchanger (34). The heating medium absorbs heat from the outdoor air in the outdoor heat exchanger (34).

Bypass Action

In the sixth embodiment, the bypass action is performed in the same manner as in the fifth embodiment. For example, when the temperature of the heating medium falls within the first temperature range and the low-temperature magnetic refrigerator (ML) does not operate, the controller (100) opens the control valve (90) of the bypass channel (60) corresponding to the low-temperature magnetic refrigerator (ML). When the temperature of the heating medium falls within the third temperature range and the high-temperature magnetic refrigerator (MH) does not operate, the controller (100) opens the control valve (90) of the bypass channel (60) corresponding to the high-temperature magnetic refrigerator (MH). Other advantages are the same as, or similar to, those of the fifth embodiment.

Variations of Fifth and Sixth Embodiments

Variations of the fifth and sixth embodiments will be described below.

Variation G - Different Frequencies

The magnetic refrigeration apparatus (1) of variation G differs from the magnetic refrigeration apparatuses of the fifth and sixth embodiments in the frequency that the heating medium falls within the temperature ranges. As illustrated in FIG. 37, the magnetic refrigeration apparatus (1) has four temperature ranges of “rare,” “low-frequency,” “medium-frequency,” and “high-frequency” in an ascending order of the frequency. The first temperature range is a “rare” temperature range, the second and sixth temperature ranges are “low-frequency” temperature ranges, the third and fifth temperature ranges are “medium-frequency” temperature ranges, and the fourth temperature range is a “high-frequency” temperature range.

In this case, the magnetic refrigeration apparatus (1) preferably has six magnetic refrigerators (M) corresponding to these temperature ranges. The magnetic refrigerator (M) corresponding to the first temperature range is referred to as a magnetic refrigerator A1, the magnetic refrigerator (M) corresponding to the second temperature range as a magnetic refrigerator A2, the magnetic refrigerator (M) corresponding to the third temperature range as a magnetic refrigerator A3, the magnetic refrigerator (M) corresponding to the fourth temperature range as a magnetic refrigerator A4, the magnetic refrigerator (M) corresponding to the fifth temperature range as a magnetic refrigerator A5, and the magnetic refrigerator (M) corresponding to the sixth temperature range as a magnetic refrigerator A6.

In this example, preferably, the less frequently the temperature of the heating medium falls within the operating temperature range of the magnetic refrigerator (M), the wider the operating temperature range of the magnetic working substance (11) of the magnetic refrigerator (M) is. In this example, the magnetic working substance (11) of the magnetic refrigerator A1 has the widest operating temperature range, the magnetic working substances (11) of the magnetic refrigerators A2 and A6 have the second widest operating temperature ranges, the magnetic working substances (11) of the magnetic refrigerators A3 and A5 have the third widest operating temperature ranges, and the magnetic working substance (11) of the magnetic refrigerator A4 has the narrowest operating temperature range.

In this example, preferably, the less frequently the temperature of the heating medium falls within the operating temperature range of the magnetic refrigerator (M), the fewer layers of magnetic working substance (11) the magnetic refrigerator (M) has. In addition, preferably, the less frequently the temperature of the heating medium falls within the operating temperature range of the magnetic refrigerator (M), the larger the total amount of the magnetic working substance (11) the magnetic refrigerator (M) has. The reasons are as described above. Variation H - Example of Cooling-Only Apparatus

A magnetic refrigeration apparatus (1) of variation H is applied to a cooling-only air conditioner. As illustrated in FIG. 38, the magnetic refrigeration apparatus (1) is obtained by removing the third and fourth four-way switching valves (37) and (38) from the magnetic refrigeration apparatus of the fifth embodiment. In the variation H, the cooling operation is performed in the same manner as in the fifth embodiment.

As illustrated in FIG. 39, the magnetic refrigeration apparatus (1) is operated in a first temperature range that the temperature of the heating medium falls within with “medium” frequency, a second temperature range that the temperature of the heating medium falls within with “high” frequency, and a third temperature range that the temperature of the heating medium falls within with “low” frequency. The low-temperature magnetic refrigerator (ML) corresponds to the first temperature range, the medium-temperature magnetic refrigerator (MM) corresponds to the second temperature range, and the high-temperature magnetic refrigerator (MH) corresponds to the third temperature range.

In this example, the high-temperature magnetic working substance (11H) has the widest operating temperature range, the low-temperature magnetic working substance (11L) has the second widest operating temperature range, and the medium-temperature magnetic working substance (11M) has the narrowest operating temperature range.

In this example, the high-temperature magnetic refrigerator (MH) has the fewest layers, the low-temperature magnetic refrigerator (ML) has the second fewest layers, and the medium-temperature magnetic refrigerator (MM) has the most layers.

In this example, the amount of the high-temperature magnetic working substance (11H) of the high-temperature magnetic refrigerator (MH) is the largest, the amount of the low-temperature magnetic working substance (11L) of the low-temperature magnetic refrigerator (ML) is the second largest, and the amount of the medium-temperature magnetic working substance (11M) of the medium-temperature magnetic refrigerator (MM) is the smallest. The reasons are as described above.

Variation I — Example of Heating-Only Apparatus

A magnetic refrigeration apparatus (1) of variation 1 is applied to a heating-only air conditioner. As illustrated in FIG. 40, the magnetic refrigeration apparatus (1) is obtained by removing the third and fourth four-way switching valves (37) and (38) from the magnetic refrigeration apparatus of the fifth embodiment. In the variation I, the heating operation is performed in the same manner as in the fifth embodiment.

As illustrated in FIG. 41, the magnetic refrigeration apparatus (1) is operated in a first temperature range that the temperature of the heating medium falls within with “low” frequency, a second temperature range that the temperature of the heating medium falls within with “high” frequency, and a third temperature range that the temperature of the heating medium falls within with “medium” frequency. The low-temperature magnetic refrigerator (ML) corresponds to the first temperature range, the medium-temperature magnetic refrigerator (MM) corresponds to the second temperature range, and the high-temperature magnetic refrigerator (MH) corresponds to the third temperature range.

In this example, the low-temperature magnetic working substance (11L) has the widest operating temperature range, the high-temperature magnetic working substance (11H) has the second widest operating temperature range, and the medium-temperature magnetic working substance (11M) has the narrowest operating temperature range.

In this example, the low-temperature magnetic refrigerator (ML) has the fewest layers, the high-temperature magnetic refrigerator (MH) has the second fewest layers, and the medium-temperature magnetic refrigerator (MM) has the most layers.

In this example, the amount of the low-temperature magnetic working substance (11L) of the low-temperature magnetic refrigerator (ML) is the largest, the amount of the high-temperature magnetic working substance (11H) of the high-temperature magnetic refrigerator (MH) is the second largest, and the amount of the medium-temperature magnetic working substance (11M) of the medium-temperature magnetic refrigerator (MM) is the smallest. The reasons are as described above.

$\text{Variation J}-\text{Another Arrangement of Third and Fourth Magnetic Refrigerators}$

Each of the low-temperature magnetic refrigerator (ML) and the high-temperature magnetic refrigerator (MH), which are the third magnetic refrigerators, may not be disposed at the end of the plurality of magnetic refrigerators, and may be disposed near the end of the plurality of magnetic refrigerators (M).

It is not necessarily required that the low-temperature magnetic refrigerator (ML) and the high-temperature magnetic refrigerator (MH), which are the third magnetic refrigerators, are adjacent to the outdoor heat exchanger (34), and may be disposed closer to the outdoor heat exchanger (34).

Suppose the whole operating temperature range of the plurality of magnetic refrigerators (M) is divided into three ranges having the same temperature width, and the lowest temperature range is defined as a “low temperature range,” the highest temperature range as a “high temperature range,” and the range between the low and high temperature ranges as a “medium temperature range.” In this case, the third magnetic refrigerator may be associated with any one of the low temperature range or the high temperature range, and the fourth magnetic refrigerator may be associated with the medium temperature range. In other words, the third magnetic refrigerator may be configured to exhibit the magnetocaloric effect in the low or high temperature range, and the fourth magnetic refrigerator may be configured to exhibit the magnetocaloric effect in the medium temperature range.

Other Embodiments

The embodiments and variations described above may be modified as follows.

The magnetic field modulator (12) may be any one of a linear drive magnetic field modulator using a permanent magnet, a rotary drive magnetic field modulator using a permanent magnet, a stationary magnetic field modulator using an electromagnet, or a stationary magnetic field modulator using an electromagnet and a permanent magnet.

The first and second heat exchange sections of the present disclosure may be comprised of other heat exchangers than the air heat exchangers. Specifically, the heat exchange sections may be heat exchangers that exchange heat between the heating medium in the heating medium circuit (C) and a different heating medium (e.g., water, brine, or a refrigerant) flowing through a secondary channel.

The solid-state refrigeration apparatus is applied to devices, such as a cooler for cooling the inside of a storage, an air conditioner, a heat pump chiller, and a hot water supply apparatus.

The solid-state refrigeration apparatus may be of any type other than a magnetic refrigeration apparatus that causes the magnetic working substance (11) to produce the magnetocaloric effect. The solid-state refrigeration apparatus includes a solid refrigerant substance configured to have a caloric effect on an external energy and an induction section configured to cause the solid refrigerant substance to produce the caloric effect. The solid refrigerant substance as used herein includes a substance with properties between liquid and solid, such as a plastic crystal.

Other types of the solid-state refrigeration apparatus include: (1) a type that causes the solid refrigerant substance to produce an electrocaloric effect; (2) a type that causes the solid refrigerant substance to produce a barocaloric effect; and (3) a type that causes the solid refrigerant substance to produce an elastocaloric effect.

An induction section of the solid-state refrigeration apparatus of the type (1) applies an electric field variation to the solid refrigerant substance. As a result, the solid refrigerant substance undergoes a phase transition from a ferroelectric substance to a paraelectric substance, for example, and thus generates or absorbs heat.

An induction section of the solid-state refrigeration apparatus of the type (2) applies a pressure variation to the solid refrigerant substance. As a result, the solid refrigerant substance undergoes a phase transition, and thus generates or absorbs heat.

An induction section of the solid-state refrigeration apparatus of the type (3) applies a stress variation to the solid refrigerant substance. As a result, the solid refrigerant substance undergoes a phase transition, and thus generates or absorbs heat.

While the embodiments and variations thereof have been described above, it will be understood that various changes in form and details may be made without departing from the spirit and scope of the claims. The embodiments and the variations thereof may be combined and replaced with each other without deteriorating intended functions of the present disclosure.

The ordinal numbers such as “first,” “second,” and “third” described above are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.

As can be seen from the foregoing description, the present disclosure is useful for a solid-state refrigeration apparatus, in particular, a magnetic refrigeration apparatus.

Claims

1. A solid-state refrigeration apparatus, comprising: a plurality of solid refrigerators each including a solid refrigerant substance configured to have a caloric effect on an external energy andan induction section configured to cause the solid refrigerant substance to produce the caloric effect;a heating medium circuit with the plurality of solid refrigerators connected thereto; anda conveying mechanism configured to convey a heating medium in the heating medium circuit,the heating medium circuit including a first channel in which the solid refrigerators are connected in series and through which the heating medium conveyed by the conveying mechanism is supplied to a first heat exchange section,a second channel in which the solid refrigerators are connected in series and through which the heating medium conveyed by the conveying mechanism is supplied to a second heat exchange section, andat least one bypass mechanism connected to at least one of the first channel and the second channel, the at least one bypass mechanism being configured to switch between an action of making the heating medium flow through the solid refrigerator andan action of making the heating medium bypass the solid refrigerator.

2. The solid-state refrigeration apparatus of claim 1, wherein the at least one bypass mechanism is connected to both of the first channel and the second channel and corresponds to each of the solid refrigerators.

3. The solid-state refrigeration apparatus of claim 1, wherein the plurality of solid refrigerators is a plurality of magnetic refrigerators each including a magnetic working substance as the solid refrigerant substance anda magnetic field modulator as the induction section configured to apply a magnetic field variation to the magnetic working substance.

4. The solid-state refrigeration apparatus of claim 3, wherein each of the magnetic refrigerators is a cascaded magnetic refrigerator including different types of magnetic working substances arranged from a low-temperature end to a high-temperature end of the magnetic refrigerator in an ascending order of Curie temperature.

5. The solid-state refrigeration apparatus of claim 4, wherein the magnetic refrigerators are connected in series in the first channel and the second channel, the magnetic refrigerators being arranged in an ascending order of average values of the Curie temperatures of the magnetic refrigerators.

6. The solid-state refrigeration apparatus of claim 3, wherein each of the magnetic refrigerators is a single-layer magnetic refrigerator having a single magnetic working substance, andthe magnetic refrigerators are connected in series in the first channel and the second channel, the magnetic refrigerators being arranged in an ascending order of Curie temperatures of the magnetic working substances of the magnetic refrigerators.

7. The solid-state refrigeration apparatus of claim 3, wherein operating temperature ranges of an adjacent pair of the magnetic refrigerators partially overlap each other.

8. The solid-state refrigeration apparatus of claim 7, wherein each of the magnetic refrigerators is a cascaded magnetic refrigerator including different types of magnetic working substances arranged from a low-temperature end to a high-temperature end of the magnetic refrigerator in an ascending order of Curie temperature,the magnetic working substances at adjacent ends of an adjacent pair of the magnetic refrigerators are configured to have operating temperature ranges having an overlapping area in which the operating temperature ranges partially or completely overlap with each other, anda maximum value of a magnetocaloric effect in the overlapping area of the operating temperature ranges is equal to or more than ½ of an average of maximum values of a magnetocaloric effect of the magnetic working substances at the adjacent ends of the adjacent pair of the magnetic refrigerators.

9. The solid-state refrigeration apparatus of claim 7, wherein each of the magnetic refrigerators is a single-layer magnetic refrigerator having a single-type magnetic working substance,the magnetic working substances of an adjacent pair of the magnetic refrigerators are configured to have operating temperature ranges having an overlapping area in which the operating temperature ranges partially overlap with each other, anda maximum value of an magnetocaloric effect in the overlapping area of the operating temperature ranges is equal to or more than ½ of an average of maximum values of a magnetocaloric effect of the magnetic working substances of the adjacent pair of the magnetic refrigerators.

10. The solid-state refrigeration apparatus of claim 4, wherein the different types of magnetic working substances include an endmost magnetic working substance located at one of ends of the different types of magnetic working substances andan intermediate magnetic working substance located between the ends, andthe endmost magnetic working substance has a wider operation temperature range than the intermediate magnetic working substance.

11. The solid-state refrigeration apparatus of claim 4, wherein the different types of magnetic working substances include an endmost magnetic working substance located at one of ends of the different types of magnetic working substances andan intermediate magnetic working substance located between the ends, anda maximum value of a magnetocaloric effect of the endmost magnetic working substance is greater than a maximum value of a magnetocaloric effect of the intermediate magnetic working substance.

12. The solid-state refrigeration apparatus of claim 11, wherein the magnetic field modulator causes an amount of change in magnetic flux density of the endmost magnetic working substance larger than an amount of change in magnetic flux density of the intermediate magnetic working substance.

13. The solid-state refrigeration apparatus of claim 11, wherein, the endmost magnetic working substance causes a larger adiabatic temperature change or entropy change than the intermediate magnetic working substance.

14. The solid-state refrigeration apparatus of claim 11, wherein the endmost magnetic working substance has a higher weight than the intermediate magnetic working substance.

15. The solid-state refrigeration apparatus of claim 14, wherein the endmost magnetic working substance has a higher filling factor or volume than the intermediate magnetic working substance.

16. The solid-state refrigeration apparatus of claim 1, wherein at least one of the first channel and the second channel has a thermal storage section through which the heating medium having bypassed the solid refrigerators flows.

17. The solid-state refrigeration apparatus of claim 3, wherein some of the magnetic refrigerators are third magnetic refrigerators and others are fourth magnetic refrigerators, andthe magnetic working substances of the third magnetic refrigerators have wider operating temperature ranges than the magnetic working substances of the fourth magnetic refrigerators.

18. The solid-state refrigeration apparatus of claim 17, wherein the third magnetic refrigerators have a larger amount of the magnetic working substances than the fourth magnetic refrigerators.

19. The solid-state refrigeration apparatus of claim 17, wherein the bypass mechanism is provided to correspond to the third magnetic refrigerators.

20. The solid-state refrigeration apparatus of claim 17, wherein when the solid-state refrigeration apparatus is in operation, a temperature of the heating medium falls within a whole operating temperature range of the third magnetic refrigerators less frequently than within a whole operating temperature range of the fourth magnetic refrigerators.

21. The solid-state refrigeration apparatus of claim 17, wherein a whole operating temperature range of the fourth magnetic refrigerators is an intermediate temperature range, anda whole operating temperature range of the third magnetic refrigerators is one or both of a low temperature range and a high temperature range.

22. The solid-state refrigeration apparatus of claim 17, wherein the third magnetic refrigerators are provided near the ends of the plurality of magnetic refrigerators.

23. The solid-state refrigeration apparatus of claim 22, wherein the third magnetic refrigerators are provided at the ends of the plurality of magnetic refrigerators.

24. The solid-state refrigeration apparatus of claim 17, wherein the third magnetic refrigerators are provided closer to an outdoor heat exchanger fonning at least one of the first heat exchange section and the second heat exchange section.

25. The solid-state refrigeration apparatus of claim 24, wherein the third magnetic refrigerators are provided adjacent to the outdoor heat exchanger.