Abstract:
A magnetic refrigeration control system, includes: a first magnetocaloric bed; a pipe, arranged through the first magnetocaloric bed; a coolant, flowing in the pipe; a pump, driving the coolant with a pumping speed; a valve, adjusting a flow period of the flowing coolant; a magnetic module, providing an increasing magnetic field to the first magnetocaloric bed during a magnetization period and providing a decreasing magnetic field to the first magnetocaloric bed during a demagnetization period; and a sensor, detecting a fluid pressure of the coolant flowing in the pipe, the temperature of a refrigerator, and a flowing rate of the coolant flowing in the pipe; and a controller, adjusting the pumping speed, the flow period, the magnetization period, and the demagnetization period according to the temperature, the fluid pressure, and the flowing rate in real time. A magnetic refrigeration control method is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The disclosure relates generally to magnetic refrigeration technologies, and more particularly relates to the control of a magnetic refrigeration system with better cooling performance. 
         [0003]    2. Description of the Related Art 
         [0004]    Present refrigeration technology, for example, a refrigerator, a freezer, a room air conditioner, a heat pump and the likes, mainly employs a gas compression/expansion cycle. However, a serious problem of environmental pollution is caused by specific Freon gases discharged into environment for refrigeration technology based on the gas compression/expansion cycle. Recently, magnetic refrigeration technology has been introduced as a highly efficient and environmentally friendly cooling technology. Magnetic refrigeration technology adapts a magnetocaloric effect (MCE) of magnetocaloric materials (MCM) to realize refrigeration cycles. 
         [0005]    Nowadays, the operation frequency of the MCM based magnetic refrigeration system is fixed. For example, the frequency and cycle of magnetization or demagnetization to a magnetocaloric material are fixed. But, the cooling environment varies. Thus, for this kind of the magnetic refrigeration system is hard to achieve the best efficiency for various cooling situations or requirements. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    An embodiment of a magnetic refrigeration control system for an outer heat exchanger, includes: a first magnetocaloric bed; a pipe, arranged through the first magnetocaloric bed; a coolant, flowing in the pipe; a pump, driving the coolant with a pumping speed; a valve, adjusting a flow period of the coolant flowing in the pipe; a magnetic module, providing an increasing magnetic field to the first magnetocaloric bed during a magnetization period, and providing a decreasing magnetic field to the first magnetocaloric bed during a demagnetization period; a sensor, detecting a fluid pressure of the coolant flowing in the pipe, the temperature of the outer heat exchanger, and a flowing rate of the coolant flowing in the pipe; and a controller, adjusting the pumping speed, the flow period, the magnetization period, and the demagnetization period according to the temperature, the fluid pressure, and the flowing rate. 
         [0007]    An embodiment of a magnetic refrigeration control method for cooling an heat exchanger, includes steps of: providing a magnetic refrigeration control system comprising a first magnetocaloric bed; a pipe arranged through the first magnetocaloric bed, and a coolant flowing in the pipe; driving the coolant with a pumping speed; adjusting a flow period of the coolant flowing in the pipe; providing an increasing magnetic field to the first magnetocaloric bed during a magnetization period, and providing a decreasing magnetic field to the first magnetocaloric bed during a demagnetization period; and detecting a fluid pressure of the coolant flowing in the pipe, the temperature of the outer heat exchanger, and a flowing rate of the coolant flowing in the pipe; adjusting the pumping speed, the flow period, the magnetization period, and the demagnetization period according to the temperature, the fluid pressure, and the flowing rate, wherein the temperature of the outer heat exchanger is determined by pumping speed, the flow period, the magnetization period and the demagnetization period. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]    The invention will become more fully understood by referring to the following detailed description with reference to the accompanying drawings, wherein: 
           [0009]      FIG. 1  is a schematic diagram illustrating an embodiment of magnetic refrigeration control system of the disclosure; 
           [0010]      FIGS. 2A-2C  are schematic diagrams illustrating an embodiment of a magnetic module for proving magnetic field to magnetocaloric beds of the magnetic refrigeration control system shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    The making and using of the embodiments of the present invention are discussed in detail below. It should be appreciated, however, that the embodiments provide many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention. 
         [0012]      FIG. 1  is a schematic diagram illustrating an embodiment of magnetic refrigeration control system of the disclosure. The magnetic refrigeration control system  100  comprises at least a controller  110 , a pump  120 , a valve  122 , a coolant  124 , a pipe  126 , a magnetic module  130 , a magnetocaloric bed  132 , a sensor  140 , and an outer heat exchanger  150 . The pump  120  and the valve  122  are connected by the pipe  126 , and the coolant  124  flows within the pipe  126 . In order to circulate the coolant  124 , the pipe  126  is constructed as a circulating pipe for example. The pump  120  drives the coolant  124  to flow, and the valve  122  adjusts the duration period of the flowing of the coolant  124  and the flowing rate of the coolant  124 . Also, the pipe  126  is arranged between the magnetocaloric bed  132  and the outer heat exchanger  150 . Therefore, the magnetocaloric bed  132  and the outer heat exchanger  150  can exchange heat with the coolant  124  flowing within the pipe  126 . 
         [0013]    The magnetocaloric bed  132  contains magnetocaloric materials (MCM). In an embodiment, when magnetocaloric material is provided with a magnetic field or an increasing magnetic field, magnetocaloric material will heat up. While the magnetic field is held constantly, the coolant  124  is provided to take away heat generated from the magnetocaloric materials. And once the magnetocaloric material is sufficiently cooled down, the magnetic field is removed or largely decreased. Finally, due to its nature of having magnetocaloric effect (MCE), the magnetocaloric material cools down. On the other hand, the coolant  124  also takes away heat from the outer heat exchanger  150  when the magnetocaloric material cools down. Due to these features, magnetocaloric refrigeration is realized. The outer heat exchanger here may be heat sink, or similar devices which can exchange heat with the coolant  124  as here described or other heat exchanging media. 
         [0014]    In an embodiment, the operations of the pump  120 , the valve  122 , and the magnetic module  130  are controlled by the controller  110 . For example, the controller  110  can adjust the pumping speed of the pump  120 , can open or close the valve  122 , and can adjust the strength or the duration period of the magnetic field provided by the magnetic module  130 . 
         [0015]    It should be noted, the cooling performance and cooling temperature gradient (the speed of temperature spreading) of magnetocaloric refrigeration depend on the material characteristics inside the magnetocaloric bed  132 , the duration period of the increasing magnetic field provided to the magnetocaloric bed  132 , the duration period of the decreasing magnetic field provided to the magnetocaloric bed  132 , the variation of the magnetic field provided to the magnetocaloric bed  132 , the fluid pressure of the coolant  124  in the pipe  126 , and the flowing rate of the coolant  124  in the pipe  126 , etc. In order to perform better cooling power or establish the cooling temperature gradient faster, in some embodiments, the sensor  140  detects working and/or environment factors such as the fluid pressure of the coolant  124  in the pipe  126 , the flowing rate of the coolant  124  in the pipe  126 , and the temperature of the outer heat exchanger  150 . And then the controller  110  adjusts the pumping speed of the pump  120 , the open duration period of the valve  122 , the duration period of the increasing magnetic field generated by the magnetic module  130  and provided to the magnetocaloric bed  132 , and the duration period of the decreasing magnetic field generated by the magnetic module  130  and provided to the magnetocaloric bed  132 , according to the parameters, such as the temperature, the fluid pressure, and the flowing rate, obtained by the sensor  140 . By feeding back these parameters from the sensor  140  to the controller  110  in real time, the controller  110  can improve the cooling power or build up temperature gradient faster. It should be known, that the margin of adjusting the pumping speed of the pump  120 , the open duration period of the valve  122 , the duration period of the increasing magnetic field generated by the magnetic module  130  and provided to the magnetocaloric bed  132 , and the duration period of the decreasing magnetic field generated by the magnetic module  130  and provided to the magnetocaloric bed  132 , are all dependent on user requirements and designs. 
         [0016]    While the magnetic refrigeration control system has been described by way of example and in terms of a brief embodiment, it is to be understood that the magnetic refrigeration control system can have not just one pump, valve, pipe, magnetocaloric bed, outer heat exchanger, and/or magnetic module, however, arrangement of the magnetic refrigeration control system depends described here on requirements or designs. Also, the arrangement of the pump, valve, pipe, magnetocaloric bed, outer heat exchanger, and/or magnetic module is not limited to that described above. 
         [0017]      FIG. 2A-2C  are schematic diagrams illustrating an embodiment of a magnetic module and magnetocaloric beds for the magnetic refrigeration control system shown in  FIG. 1 . Refer to  FIGS. 1 ,  2 A,  2 B, and  2 C, the magnetic module  130  comprises a magnet  210  and a driving means  220 , and the driving means  220  is controlled by the controller  110 . The axle center C of the magnet  210  is connected to the driving means  220 . Thus, the driving means  220  drives the magnet  210  to rotate via the power provided from the controller  110 . The magnet  210  described above may be a permanent magnet, a super conductor based magnet, or a set of electro-coils with an outer electrical circuit, and in this embodiment, the magnet  210  is a permanent magnet, but is not to limit this invention. 
         [0018]    In this embodiment, four magnetocaloric beds  202 ,  204 ,  206 , and  208  are arranged beside the magnet  210 . A vector V represents the direction from the axle center C to the magnetic pole P of the magnet  210 . When the magnetic pole P rotates to a 0 degree angle, the vector V points to the magnetocaloric bed  202 . When the magnetic pole P then rotates to a 90 degree angle, the vector V points to the magnetocaloric bed  204 . When the magnetic pole P then rotates to a 180 degree angle, the vector V points to the magnetocaloric bed  206 . When the magnetic pole P then rotates to a 270 degree angle, the vector V points to the magnetocaloric bed  208 . When the magnetic pole P then further rotates to a 360 degree angle, the vector V points to the magnetocaloric bed  202  again, i.e. the magnetic pole P rotates for a complete circle and finally back to its original position where is also at 0 degree. Thus, when the driving means  220  drives the magnetic pole P to rotate from a 0 degree angle to 90 degree angle, viewed as aspects of the magnetocaloric beds  202  and  204 , an increasing magnetic field is provided to the magnetocaloric bed  204  by relatively rotating of the magnet  210 , and a decreasing magnetic field is provided to the magnetocaloric bed  202  by relatively rotating of the magnet  210 . It should be known, that the driving means  220  can drive the magnetic pole P to rotate from a 90 degree angle back to 0 degree angle. Accordingly, viewed as aspects of the magnetocaloric beds  202  and  204 , a decreasing magnetic field is provided to the magnetocaloric bed  204  by relatively rotating of the magnet  210 , and an increasing magnetic field is provided to the magnetocaloric bed  202  by relatively rotating of the magnet  210 . 
         [0019]    Also, different variation rates and/or quantity of the magnetic field provided to the magnetocaloric bed cause different performances and cooling gradients for magnetocaloric refrigeration. Thus, the controller  110  can adjust a driving means operation frequency of the driving means  220 , in order to perform a proper cooling gradient corresponding to user requirements or designs. 
         [0020]    In some embodiments, when rotating the magnetic pole P from a 0 degree angle to 90 degree angle, the driving means  220  only drives the magnetic pole P to rotate to a proper degree of angle larger than a 45 degree angle (such as 45.1, 46, or 50 degrees, . . . etc), as shown in  FIG. 2B . When the magnetic pole P reaches a determined degree angle, the driving means  220  stops driving the magnet  210  from rotating, namely the controller  110  stops providing the power or reducing the power to the driving means  220  at this time. Due to the magnetocaloric beds  202 ,  204 ,  206 , and  208  containing of magnetocaloric materials which is basically magnetic contractive, and wherein the distance between the magnetic pole P and the magnetocaloric bed  204  is less than the distance between the magnetic pole P and the magnetocaloric bed  202 , the magnetic pole P will rotate to a 90 degree angle automatically by the magnetic attraction force between the magnetic pole P and the magnetocaloric bed  204 , as shown in  FIG. 2C . When the magnet  210  requires rotating, or a decreasing magnetic field is required to be provided to the magnetocaloric bed  204 , the driving means  220  will start to drive the magnet  210  to rotate. Due to the magnet  210  rotates automatically such that the driving means  220  not being required to be provided power all the time, the total consumption of power can be further reduced. 
         [0021]    Those who are skilled in this technology field can delete, add, or change the arrangement of the magnetocaloric bed, magnet, and/or driving means described above without departing from the scope and spirit of this invention. For example, there can be eight magnetocaloric beds in the magnetic refrigeration control system, and the magnetocaloric beds may be arranged in a circular path with the axle center C as a center, wherein the eight magnetocaloric beds are disposed at 0, 45, 90, 135, 180, 225, 270, and 315 degree angles respectively. Thus, when rotating the magnetic pole P from a 0 degree angle to 45 degree angle, the driving means  220  can drive the magnetic pole P to rotate to a degree angle just larger than a 22.5 degree angle. 
         [0022]    While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. Those who are skilled in this technology can still make various alterations and modifications without departing from the scope and spirit of this invention. Therefore, the scope of the present invention shall be defined and protected by the following claims and their equivalents.