Active Magnetic Refrigerator

Abstract

An active magnetic refrigerator includes separated hot and cold heat exchange units wherein a heat transfer fluid that exchanges a heat with a magnetic heat exchange unit having the magnetocaloric material pieces arranged to have a gap therebetween separately circulates through a solenoid valve.

1 . An active magnetic refrigerator, comprising:
 first and second heat exchange units including a magnetocaloric material for passing a flow of a heat transfer fluid;   a magnet unit for applying a magnetic field to one of the first heat exchange unit and the second heat exchange unit or erasing the magnetic field from the first heat exchange unit or the second heat exchange unit;   a hot heat exchanger for coupled to the first heat exchange unit and the second heat exchange unit for a circulation;   a cold heat exchanger for coupled to the first heat exchange unit and the second heat exchange unit for the circulation;   a first solenoid valve for directing a first heat transfer fluid exhausted from the hot heart exchanger to one of the first heat exchange unit and the second heat exchange unit having the magnetic field applied thereto; and   a second solenoid valve for directing a second heat transfer fluid exhausted from the cold heart exchanger to one of the second heat exchange unit and the first heat exchange unit having the magnetic field erased therefrom.   
   
   
       2 . The refrigerator in accordance with  claim 1 , wherein the magnet unit comprises a first electromagnet attached to the first heat exchange unit, and a second electromagnet attached to the second heat exchange unit. 
   
   
       3 . The refrigerator in accordance with  claim 1 , wherein the magnet unit comprises a permanent magnet and a permanent magnet conveying member for moving the permanent magnet to one of the first heat exchange unit and the second heat exchange unit. 
   
   
       4 . The refrigerator in accordance with  claim 3 , wherein the permanent magnet conveying member comprises a yoke having the permanent magnet disposed at both sides thereof, and a reciprocation transfer member for reciprocating of the yoke. 
   
   
       5 . The refrigerator in accordance with  claim 4 , wherein the reciprocation transfer member comprises a rack attached to the yoke, a pinion engaged with the rack, and a motor for transferring a rotational power to the pinion. 
   
   
       6 . The refrigerator in accordance with  claim 1 , wherein the magnet unit comprises a magnet and a magnet rotating assembly for rotating the magnet, and
 further comprising a plurality of mounting parts for mounting the first heat exchange unit and the second heat exchange unit, the mounting part being disposed on a rotational plane of the magnet, a through-hole having the magnet rotating assembly mounted at a center thereof, and a table for constituting a connecting path for connecting the heat exchangers and the magnetic heat exchange units.   
   
   
       7 . The refrigerator in accordance with  claim 6 , wherein the connecting path of a portion at a crossing of the first heat transfer fluid and the second heat transfer fluid comprises a tunnel and a bridge. 
   
   
       8 . The refrigerator in accordance with  claim 7 , wherein the magnet rotating assembly comprises a flange supporting the magnet disposed upper and lower sides of one of the first heat exchange unit and the second heat exchange unit, a yoke consisting of a web connecting the flange, and a rotational power transfer member for transferring a rotational power to the yoke. 
   
   
       9 . The refrigerator in accordance with  claim 1 , wherein the first heat exchange unit comprises a first case including the magnetocaloric material, an upper inlet port and an upper outlet port disposed on an upper surface of the first case, and an lower inlet port and an lower outlet port disposed on an lower surface of the first case, and
 wherein the second heat exchange unit comprises a second case including the magnetocaloric material, an upper inlet port and an upper outlet port disposed on an upper surface of the second case, and a lower inlet port and a lower outlet port disposed on a lower surface of the second case.   
   
   
       10 . The refrigerator in accordance with  claim 9 , wherein the magnetocaloric material comprises a plurality of magnetocaloric material pieces disposed in the first case or the second case, the plurality of magnetocaloric material pieces have a gap therebetween. 
   
   
       11 . The refrigerator in accordance with  claim 10 , wherein each of the plurality of magnetocaloric material pieces comprises a gadolinium plate. 
   
   
       12 . The refrigerator in accordance with  claim 10 , wherein each of the plurality of magnetocaloric material pieces comprises a gadolinium rod having a constant circular cross-section in the lengthwise direction. 
   
   
       13 . The refrigerator in accordance with  claim 12 , wherein the gadolinium rod comprises a groove in the lengthwise direction.