Apparatus and method for magnetic refrigeration

Abstract

A system for magnetic refrigeration is provided. The system includes a layered structure formed by coupling an array of Peltier modules and an array of magnetocaloric material (MCM) components. Each Peltier module of the plurality of Peltier modules is sandwiched between two MCM components of the plurality of MCM components. The system further includes a power supply configured to simultaneously supply power to each Peltier module in the array of Peltier modules. The current in each powered Peltier module flows in a unidirectional manner. The system further includes a magnetic source configured to apply a spatially uniform magnetic field to the array of MCM components.

Description

[Technical Field]

[0001] Technical Field FIELD OF THE DISCLOSURE The present disclosure relates generally to magnetic refrigeration, and more particularly to apparatus and methods utilizing magnetocaloric material (MCM) components and Peltier modules to provide magnetic refrigeration. [Background technology]

[0002] background Magnetic refrigeration is a technology used to cool substances, such as solid materials, liquids, or gases, using a magnetic field. Magnetic refrigeration is a promising and environmentally friendly technology compared to other existing technologies used to cool substances, such as vapor compression technology. Magnetic refrigeration is based on the principle of the magnetocaloric effect, where magnetocaloric materials (MCMs) are used for refrigeration, and the temperature of the MCMs can be controlled by applying a magnetic field to the MCMs.

[0003] One of the limitations of using MCMs is that they experience relatively small temperature changes (e.g., about 5 K) when subjected to moderately available magnetic field strengths (e.g., 1–2 Tesla). Furthermore, from an implementation perspective, MCMs must be combined with other mechanisms to induce heat flow between them because they are solid refrigerants and cannot be easily transferred between two spatially separated environments.

[0004] MCMs can be used in a variety of applications, such as heating, ventilation, and air conditioning (HVAC) systems. Home HVAC systems can include, for example, refrigerators that utilize magnetic refrigerators based on MCMs for cooling purposes. Conventional magnetic refrigerators exchange heat between a high-temperature environment and a low-temperature environment using a working fluid that flows between the low-temperature and high-temperature environments through the MCM. Conventional magnetic refrigerators require pumps and valve systems to control the flow of the working fluid, which inevitably complicates the design of the magnetic refrigerator and further increases the manufacturing and maintenance costs of the magnetic refrigerator.

[0005] Additionally, Peltier modules are another simple, lightweight, solid-state cooling device that can be utilized in magnetic refrigerators. Peltier modules utilize the thermoelectric effect to transfer heat from a low-temperature environment to a high-temperature environment. Peltier modules utilize an applied current or voltage to induce heat flow. However, one drawback of using Peltier modules is that their efficiency, as quantified by their coefficient of performance (COP), decreases rapidly over a large required temperature range (e.g., the required temperature difference between the low-temperature and high-temperature environments).

[0006] Therefore, to address the above-mentioned problems, there is a need for an improved device that can overcome the above-mentioned drawbacks. Summary of the Invention

[0007] overview The present disclosure provides an apparatus and method for magnetic refrigeration, i.e., a control protocol for the magnetic field applied to the MCM and / or the current applied to the Peltier module.

[0008] Some embodiments disclose an apparatus for magnetic refrigeration. The apparatus includes a layered structure formed by connecting an array of Peltier modules and an array of MCM components. Each Peltier module of the plurality of Peltier modules is sandwiched between two MCM components of the plurality of MCM components. The apparatus further includes a power supply configured to simultaneously supply power to each Peltier module in the array of Peltier modules. The current in each powered Peltier module flows in a unidirectional manner. The apparatus further includes a magnetic source configured to apply a spatially uniform magnetic field to the array of MCM components.

[0009] Some embodiments are based on the recognition that conventional cooling devices utilizing MCMs require pumps and valve systems that complicate the design of the magnetic cooling device and further increase the manufacturing and maintenance costs of the magnetic cooling device.

[0010] Some embodiments are based on the recognition that conventional cooling devices utilizing Peltier modules reduce the overall efficiency of the cooling device when a large temperature range is required.

[0011] Some embodiments are based on the recognition that a layered structure formed by integrating MCM components and Peltier modules transfers heat from a low-temperature environment to a high-temperature environment. In the layered structure, the number of MCM components is greater than the number of Peltier modules. The MCM components and Peltier modules are spatially interleaved. Because heat transfer between the MCM components is performed by the Peltier modules, integrating the MCM components with the Peltier modules can reduce the number of pumps and valve systems required.

[0012] Some embodiments recognize that the first layer of the layered structure is the first MCM component, and the last layer of the layered structure is the last MCM component, such that both MCM components directly interact with the environment. Furthermore, each Peltier module in the layered structure is sandwiched between adjacent MCM components. Because the Peltier modules in the layered structure do not directly interact with the environment, heat transfer between the Peltier modules and the environment is reduced, resulting in improved efficiency, measured as COP, compared to conventional cooling devices.

[0013] Some embodiments are based on the realization that a spatially uniform magnetic field can be generated using a pair of coils or permanent magnets. During the cooling cycle of the layered structure, the current applied to each Peltier module is the same, constant in time, and flows in a unidirectional manner.

[0014] Some embodiments disclose a method for magnetic refrigeration. The method includes forming a layered structure by coupling an array of Peltier modules with an array of magnetocaloric material (MCM) components. Each Peltier module of the plurality of Peltier modules is sandwiched between two MCM components of the plurality of MCM components. The method further includes simultaneously applying a current to each Peltier module in the array of Peltier modules using a power source. The current in each powered Peltier module flows in a unidirectional manner. The method further includes applying a spatially uniform magnetic field to the array of MCM components of the plurality of MCM components using a magnetic source. Embodiments of the present disclosure will now be further described with reference to the accompanying drawings, which are not necessarily to scale, emphasis instead being placed upon illustrating the principles of embodiments of the present disclosure. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 illustrates an exemplary apparatus for performing magnetic refrigeration, in accordance with some embodiments of the present disclosure. [Figure 2A] 1A-1C illustrate exemplary configurations of Peltier modules according to some embodiments of the present disclosure. [Figure 2B] FIG. 1 illustrates a three-parameter model of a Peltier module, according to some embodiments of the present disclosure. [Figure 3A] FIG. 1 illustrates a first exemplary configuration of an apparatus for performing magnetic refrigeration, in accordance with some embodiments of the present disclosure. [Figure 3B] FIG. 1 illustrates a second exemplary configuration of an apparatus for performing magnetic refrigeration, in accordance with some embodiments of the present disclosure. [Figure 3C] FIG. 10 illustrates a third exemplary configuration of an apparatus for performing magnetic refrigeration, in accordance with some embodiments of the present disclosure. [Figure 4]1 is a graph illustrating different coefficients of performance (COP) corresponding to devices including different numbers of magnetocaloric material (MCM) components, according to some embodiments of the present disclosure. [Figure 5] 1 is a graph illustrating temperature distribution at four critical points in the cooling cycle of an apparatus according to some embodiments of the present disclosure. [Figure 6] 1 is a flowchart illustrating a method for performing magnetic refrigeration using an apparatus according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] Detailed Description An object of some embodiments is to disclose an apparatus for performing magnetic refrigeration. Another object of some embodiments is to disclose a method for performing magnetic refrigeration. The apparatus for performing magnetic refrigeration proposed in the present disclosure may include a layered structure. The layered structure may be formed by coupling an array of Peltier modules with an array of magnetocaloric material (MCM) components. The array of MCM components and Peltier modules reduces the number of pumps and valve systems required compared to conventional systems that require a pump and valve system for each MCM module, because the proposed apparatus uses the Peltier modules to transfer heat between the MCM components. Furthermore, in conventional systems that utilize Peltier modules, the Peltier modules may be in direct contact with the environment, limiting the heat transferred to the environment and reducing the efficiency of the system. In contrast, the layered structure of the apparatus disclosed herein includes the first and last layers that contact the environment as MCM components of the multiple MCM components. Therefore, heat transfer between the multiple Peltier modules and the environment is enhanced, resulting in improved efficiency, measured as a coefficient of performance (COP), compared to conventional systems or cooling devices.

[0017] The proposed device of the present disclosure can be utilized in a variety of applications, such as heating ventilation and air conditioning (HVAC) systems.

[0018] Typically, the core of magnetic cooling in HVAC systems is the magnetocaloric (MC) effect: the application of a magnetic field increases the temperature of the MCM, and the removal of the magnetic field decreases the temperature of the MCM. Magnetic cooling requires a magnetic field source, generated using an external coil or permanent magnet. The magnetic cooling cycle corresponding to magnetic cooling can be divided into four stages. In the first stage of the magnetic cooling cycle, the MCM enters the magnetic field generated by the external magnetic field source and becomes hot. In the second stage of the magnetic cooling cycle, the hot MCM dissipates heat into the hot environment, causing its temperature to decrease. In the third stage of the magnetic cooling cycle, the MCM leaves the magnetic field and its temperature becomes lower than that of the MCM in the second stage. In the fourth stage, the MCM absorbs heat from the cold environment, causing its temperature to increase. The temperature changes due to the application and removal of the magnetic field in the first and third stages are caused by the magnetization and demagnetization of the MCM. The actual cooling occurs in the fourth stage.

[0019] For example, MCMs made from gadolinium (Gd) material have an observed temperature change of about 5°C when a 2 Tesla magnetic field is applied. To maintain a wide temperature range (e.g., temperature change), a heat generation or thermal cascade mechanism may be required.

[0020] A conventional magnetic refrigeration cycle includes a working fluid and a bidirectional pump. Furthermore, a high-temperature heat exchanger and a low-temperature heat exchanger are required to exchange heat with the high-temperature and low-temperature environments, respectively. In a conventional magnetic refrigeration cycle configuration, for example, a long array of magnetically coupled magnetic coils (MCMs) is used. The external magnetic field can be generated using a permanent magnet. Operation can be defined as two stages. In the first stage, the magnetic field of the MCM is removed. The MCM becomes cold. Therefore, the working fluid flows in the same direction as the working fluid leaving the cold MCM and entering the low-temperature heat exchanger, cooling the low-temperature environment. In the second stage, a magnetic field is applied to the MCM. The MCM becomes hot. The working fluid flows in the opposite direction, and the working fluid leaving the MCM enters the high-temperature heat exchanger, releasing heat into the high-temperature environment. This process is repeated to continuously transfer heat from the low-temperature environment to the high-temperature environment.

[0021] The rationale behind using a working fluid is that MCMs, being solid materials, are less mobile than working fluids. Therefore, once a working fluid is included, pumps or valve components are required in conventional systems. Furthermore, the pumps or valve components must be synchronized with the changes in the magnetic field. This inevitably makes the cooling device complex in conventional cooling systems. To overcome the drawbacks of conventional cooling systems, the proposed device can reduce the use of pumps and valve systems. Details of the device and method for magnetic refrigeration are further provided, for example, in Figures 1-6.

[0022] 1 illustrates an exemplary apparatus 100 for magnetic refrigeration according to one embodiment of the present disclosure. The apparatus 100 may include a layered structure formed by coupling an array of Peltier modules 104 with an array of MCM components 102. The plurality of MCM components 102 may include n MCM components, e.g., a first MCM component 102A, a second MCM component 102B, a third MCM component 102N, and an Nth MCM component 102N. The plurality of Peltier modules 104 may include n Peltier modules, e.g., a first Peltier module 104A, a second Peltier module 104B, and a third Peltier module 104C.

[0023] Each Peltier module of the plurality of Peltier modules 104 may be sandwiched between two MCM components of the plurality of MCM components 102. Thus, the number of Peltier modules of the plurality of Peltier modules 104 may be less than the number of MCM components of the plurality of MCM components 102. For example, the first Peltier module 104A may be sandwiched between the first MCM component 102A and the second MCM component 102B. The second Peltier module 104B may be sandwiched between the second MCM component 102B and the third MCM component 102C. The third Peltier module 104C may be sandwiched between the third Peltier module 104C and the Nth MCM component 102N.

[0024] In some embodiments, the first layer of the layered structure may be the first MCM component 102A in an array of multiple MCM components 102, and the last layer of the layered structure may be the last MCM component in the array of multiple MCM components 102. The first and last layers may be end layers of the layered structure. For example, the first layer may correspond to the first MCM component 102A in the layered structure. The last MCM component may correspond to the Nth MCM component 102N of the multiple MCM components 102. Thus, the first MCM component 102A and the Nth MCM component 102N (e.g., the last MCM component) in the layered structure may be in direct contact with the environment. In conventional cooling devices, the Peltier module is in direct contact with the environment, potentially causing heat loss to the environment. In contrast, in the device of the present disclosure, the first MCM component 102A and the Nth MCM component 102N are in direct contact with the environment, and the Peltier module is not in contact with the environment, thereby reducing or eliminating heat loss.

[0025] In some embodiments, the second layer of the layered structure is the first Peltier module 104A, the third layer of the layered structure is the second MCM component 102B, and the fourth layer of the layered structure is the second Peltier module 104B. The second layer of the stacked structure is adjacent to the first layer of the stacked structure. The second MCM component 102B, corresponding to the third layer, is sandwiched between the first Peltier module 104A and the second Peltier module 104B. Similarly, the third MCM component 102C may be sandwiched between the second Peltier module 104B and the third Peltier module 104C. Thus, the layered structure has an arrangement of alternating MCM components and Peltier modules such that the end layers of the layered structure are MCM components of the plurality of MCM components 102.

[0026] In some embodiments, each MCM component of the plurality of MCM components 102 may be composed of a gadolinium alloy. Gadolinium has both paramagnetic and ferromagnetic properties. Gadolinium is paramagnetic at room temperature and becomes ferromagnetic when cooled to low temperatures (20° C.). Gadolinium alloys may include different types of doping.

[0027] In some embodiments, the thickness of each MCM component in the array of MCM components 102 ranges from 0.1 centimeters (cm) to 1 cm. The thickness of each MCM component in the array of MCM components 102 may be the same. For example, the first MCM component 102A, the second MCM component 102B, the third MCM component 102N, and the Nth MCM component 102N may have a thickness of 0.5 cm. In another example, the first MCM component 102A, the second MCM component 102B, the third MCM component 102N, and the Nth MCM component 102N may have a thickness of 0.7 cm. In one embodiment, the thickness of each MCM component in the array of MCM components 102 may be different. For example, the thickness of the first MCM component 102A may be 0.4 cm, the thickness of the second MCM component 102B may be 0.7 cm, the thickness of the third MCM component 102N may be 0.2 cm, and the thickness of the Nth MCM component 102N may be 0.5 cm.

[0028] In some embodiments, each Peltier module of the plurality of Peltier modules 104 includes an n-doped semiconductor electrically connected to a p-doped semiconductor, which may be arranged in parallel with the n-doped semiconductor. The n-doped semiconductor and the p-doped semiconductor are arranged across two metal plates. The p-doped semiconductor and the n-doped semiconductor are thermally parallel and electrically connected in series. Details of the plurality of Peltier modules 104 are further described, for example, in FIG. 2A.

[0029] The device 100 further includes a power supply configured to simultaneously supply power to each Peltier module in the array of Peltier modules 104. The current through each powered Peltier module flows in a fixed direction. By controlling the current direction, the heat flow through the Peltier modules 104 can be controlled. Thus, the Peltier modules 104 can be utilized to transfer heat from one side to another. In the device 100, each Peltier module can be configured to transfer heat from one MCM component to another adjacent MCM component in the plurality of MCM components 102. For example, the first Peltier module 104A can transfer heat from the first MCM component 102A to the second MCM component 102B. Similarly, the second Peltier module 104B can transfer heat from the second MCM component 102B to the third MCM component 102C. Details of the power supply for the Peltier modules 104 are further described, for example, in FIG. 2A .

[0030] The apparatus 100 further includes a magnetic source configured to apply a spatially uniform magnetic field to the array of MCM components 102. In one embodiment, the magnetic source may be a magnetic coil. In another embodiment, the magnetic source may be a permanent magnet. As described above, the MCM components 102 can generate heat when the spatially uniform magnetic field is applied. Similarly, the MCM components 102 can cool when the spatially uniform magnetic field is removed. Such heating and cooling principles may be utilized by the apparatus 100 for magnetic cooling purposes in HVAC systems. An exemplary magnetic source is further described in FIG. 3A.

[0031] 2A illustrates an exemplary Peltier module configuration 200A according to one embodiment of the present disclosure. The exemplary configuration 200A may be implemented for each Peltier module in an array of Peltier modules 104. The illustrated exemplary configuration 200A is for a first Peltier module 104A. The first Peltier module 104A includes an n-doped semiconductor 202A electrically connected to a p-doped semiconductor 202B, which is arranged in parallel with the n-doped semiconductor 202A. The n-doped semiconductor 202A and the p-doped semiconductor 202B may be arranged across two metal plates, such as metal plate 204A and metal plate 204B. The p-doped semiconductor 202B and the n-doped semiconductor 202A are thermally parallel and electrically connected in series. The exemplary configuration 200A further illustrates a power supply 206 configured to simultaneously provide power to each Peltier module in the array of Peltier modules 104, for example, the first Peltier module 104A.

[0032] When a current is applied along direction 208, both charge carriers, e.g., holes in p-doped semiconductor 202B and electrons in n-doped semiconductor 202A, move from the top to the bottom. This movement of charge carriers generates a heat flow from the top to the bottom, independent of the environmental temperature (e.g., the ambient temperature of device 100). Therefore, by controlling the direction 208 in which the current is applied, the heat flow can be controlled. For example, the heat flow may be generated from the top to the bottom or from the bottom to the top.

[0033] In some embodiments, the n-doped semiconductor 202A and the p-doped semiconductor 202B are at least one of a silicon-based semiconductor or a bismuth telluride-based semiconductor. The materials used for the Peltier modules 104 should be thermoelectric materials. For example, silicon and bismuth telluride are thermoelectric materials. In one embodiment, the n-doped semiconductor 202A and the p-doped semiconductor 202B may be lead telluride-based semiconductors. The materials for the Peltier modules 104 may be selected based on one or more parameters associated with the Peltier modules 104, such as thermal conductivity K, Seebeck effect S, and electrical resistance R. A three-parameter model of the Peltier modules 104 is further illustrated in FIG. 2B.

[0034] 2B illustrates a three-parameter model 200B of each Peltier module according to one embodiment of the present disclosure. The three parameters may be thermal conductivity K, Seebeck effect S, and electrical resistance R associated with the plurality of Peltier modules 104. By applying a current (I) along direction 208, charge carriers, e.g., both electrons in the p-doped semiconductor 202A and holes in the p-doped semiconductor 202B, move along direction 210, i.e., from left to right.

[0035] Applying a current I to a Peltier module, e.g., the first Peltier module 104A, produces two effects: a convective contribution to heat flow, expressed as “SIT” (where I is the current and T is the temperature), and an ohmic loss term I 2 R and

[0036] The conduction of the first Peltier module 104A is given by the following equation:

number

[0037] The Seebeck effect S of the first Peltier module 104A is expressed by the following formula:

number

[0038] The heat flow generated in the first Peltier module 104A is expressed by the following equation:

number

[0039] If the temperature difference (ΔT) between two adjacent environments is known, then the heat flow into the left and out the right due to an applied current (I) is given by the following equations:

number

[0040] The parameters of Equations 5 and 6 can be determined using the specifications of multiple Peltier modules 104.

[0041] Exemplary parameters of the specifications for the Peltier modules 104 are shown in the table below. [Table 1] TIFF2025536156000007.tif68159

[0042] Furthermore, Equation 6 makes it possible to quantify the performance of the multiple Peltier modules 104. One important figure of merit is the COP (Coefficient of Performance), which is defined by the ratio of cooling power and input work for the multiple Peltier modules 104. The COP of the multiple Peltier modules 104 is defined by the following equation:

number

[0043] The higher the COP, the more efficient the cooling capacity of the device 100.

[0044] An exemplary configuration of device 100 is further described in Figures 3A, 3B, and 3C.

[0045] 3A illustrates a first exemplary configuration 300A of an apparatus 100 for magnetic refrigeration in accordance with one embodiment of the present disclosure. The exemplary configuration 300A of the apparatus 100 illustrates an alternative arrangement of multiple MCM components 102 and multiple Peltier modules 104. The first layer is the first MCM component 102A, and the last layer is the Nth MCM component 102N.

[0046] In some embodiments, in exemplary configuration 300A, at least the first MCM component 102A and the last MCM component (e.g., the Nth MCM component 102N) in the array of MCM components 102 are connected to a cooling unit 302. Cooling unit 302 may include at least one of pipes 304, a working fluid, and a heat exchanger 306. Heat exchanger 306 may include a high-temperature heat exchanger 306A and a low-temperature heat exchanger 306B. Exemplary configuration 300A may further include magnetic coils 308 as a magnetic source, such as magnetic coils 308A and 308B.

[0047] When a magnetic field is applied to device 100 using magnetic coils 308A and 308B, each MCM component in plurality of MCM components 102 generates heat. When the magnetic field is removed from device 100, the plurality of MCM components 102 cool. The first layer including first MCM component 102A and the last layer including Nth MCM component 102N are in direct contact with two working fluids. The working fluids contact first MCM component 102A and Nth MCM component 102N via pipe 304. The working fluids exchange heat with high-temperature heat exchanger 306A and low-temperature heat exchanger 306B.

[0048] In some embodiments, at least the first MCM component 102A and the last MCM component 102N in the array of MCM components 102 have a porous structure. Direct contact between the first MCM component 102A and the last MCM component 102N, which have a porous structure, can improve heat transfer between the first MCM component 102A and the last MCM component 102N and the working fluid, which is crucial for improving COP. In one embodiment, each MCM component in the array of MCM components 102 has a porous structure.

[0049] 3B illustrates a second exemplary configuration 300B of the apparatus 100 for magnetic refrigeration in accordance with an embodiment of the present disclosure. The second exemplary configuration 300B illustrates another type of refrigeration unit that does not include a high-temperature heat exchanger 306A.

[0050] In some embodiments, the first MCM component 102A or the last MCM component in an array of multiple MCM components 102 can receive cooling air via fan 310. For example, the first MCM component 102A can be cooled using fan 310. In this case, the cooling unit need not include high-temperature heat exchanger 306A because the cooling is provided by fan 310. Thus, second exemplary configuration 300B can further reduce the number of pipes 304 required to cool multiple MCM components 102. Therefore, apparatus 100 can be economically less expensive and less complex than conventional cooling systems.

[0051] 3C illustrates a third exemplary configuration 300C of the apparatus 100 for magnetic refrigeration in accordance with one embodiment of the present disclosure. The third exemplary configuration 300C illustrates a plurality of MCM components 312 having different doping amounts. The plurality of MCM components 312 may include a first MCM component 312A, a second MCM component 312B, a third MCM component 312C, and an Nth MCM component 312N.

[0052] The doping amount of the MCM components 312 may depend on the temperature range required for the device 102. The MCM components 312 may be doped to further enhance the cooling performance of the device 100. For example, the first MCM component 312A may be selected based on the temperature of the low-temperature heat exchanger 306B. Similarly, the Nth MCM component 312N may be selected based on the temperature of the high-temperature heat exchanger 306A. Thus, in the third exemplary configuration 300C, each MCM component can function in a different temperature range.

[0053] Furthermore, it is possible to determine the optimal number of MCM components among the plurality of MCM components 102. The difference in COP for different numbers of MCM components is shown in FIG.

[0054] 4 is a graph 400 illustrating different COPs corresponding to apparatus 100 including different numbers of MCM components, according to one embodiment of the present disclosure. Graph 400 includes an x-axis 402 representing COP and a y-axis 404 representing current.

[0055] The current applied to each Peltier module of the plurality of Peltier modules 104 generates a heat flow from bottom to top, i.e., from the cold environment corresponding to the cold heat exchanger 306B to the hot environment corresponding to the hot heat exchanger 306A. In principle, the current applied to each Peltier module may be different. The current applied to each Peltier module may also be time-dependent. Such flexibility may be explored to further enhance cooling performance.

[0056] In the device 100, the current applied to each Peltier module of the plurality of Peltier modules 104 is the same and constant over time. Graph 400 shows the relationship between COP and current for three, four, five, six, and seven MCM components of the plurality of MCM components 102. Furthermore, using "N" MCM components requires "N-1" Peltier modules.

[0057] Furthermore, the time dependence of the magnetic field is assumed to be:

number

[0058] The dotted line 406 represents the optimal COP achieved using only Peltier modules in a conventional cooling device. The COP value of the conventional cooling device is approximately 3.5. The COP of the device 100 including the array of multiple MCM components 102 and multiple Peltier modules 104 increases to approximately 9.5, which is approximately 2.6 times greater than the optimal value achieved using only Peltier modules in a conventional cooling device. Thus, the device 100 improves the COP compared to the conventional cooling device. Furthermore, the COP value appears to saturate when the number of MCM components is increased beyond seven. Furthermore, the temperature distribution at different times during the cooling cycle of the device 100 is illustrated in FIG. 5.

[0059] 5 is a graph 500 illustrating temperature distribution at four critical times in the cooling cycle of device 100, according to one embodiment of the present disclosure. Graph 500 includes an x-axis 502 representing temperature (K) and a y-axis 504 representing position (cm) relative to device 100.

[0060] Four critical times, e.g., t=0 - , 0 + , P0 - / 2, P0+ The spatial temperature distribution of a cooling cycle such as 1 / 2 is shown. The temperature distribution is induced by an applied current and has a spike across the multiple Peltier modules 104. The end MCM components, e.g., the first MCM component 102A and the Nth MCM component 102N, may be hotter than the hot environment or colder than the cold environment. This enhances heat transfer between the multiple MCM components 102 and the environment. The overall design strategy of the device 100 is further described.

[0061] The first step is to determine the number of MCM components in the array of MCM components 102. In some embodiments, the number of MCM components in the array of MCM components 102 is determined based on the required difference in temperature (e.g., temperature range) between the first MCM component 102A and the last MCM component (e.g., the Nth MCM component 102N) in the array of MCM components 102. The application and removal of a magnetic field can only induce a temperature change of dT (<5K). The required temperature range T 範囲 For a given number of MCM components, the required number is given by:

number

[0062] The second step is to determine the thickness of the multiple MCM components 102. Due to entropy considerations, thin MCM components may be preferable. In practice, the thickness of each MCM component in the array of multiple MCM components 102 ranges from 0.1 cm to 1 cm.

[0063] The third step is to determine the current to be applied to the plurality of Peltier modules 104. In some embodiments, the amount of current provided to each powered Peltier module is determined to maximize the COP based on the number of MCM components selected to provide magnetic cooling and the target temperature range. The applied current may be determined using graph 400. The applied current may be selected based on the number of MCM components required to achieve an optimal COP, for example, 9.5. As shown in graph 400, when the number of MCM components is 7, the COP is approximately 10. The current for a COP of 10 is approximately 0.02 amps. Thus, the device 100 may be designed by selecting the number of MCM components in the plurality of MCM components 102, the thickness of the MCM components, and the current to be applied to the plurality of Peltier modules 104.

[0064] FIG. 6 illustrates a flow chart of a method 600 for performing magnetic refrigeration using apparatus 100 according to one embodiment of the present disclosure.

[0065] In step 602, a layered structure is formed by coupling an array of Peltier modules 104 with an array of MCM components 102. Each Peltier module of the Peltier modules 104 is sandwiched between two MCM components of the MCM components 102. Details of the layered structure are further provided in, for example, FIG.

[0066] In step 604, power is simultaneously supplied to each Peltier module in the array of Peltier modules 104 using the power supply 206. The current in each powered Peltier module flows unidirectionally. Further details of powering the multiple Peltier modules 104 are provided, for example, in FIG. 2A.

[0067] In step 606, a magnetic source 308 is used to apply a spatially uniform magnetic field to the array of MCM components 102. Details of magnetic source 308 are further provided in, for example, Figure 3A.

[0068] The above description provides exemplary embodiments only and is not intended to limit the scope, application, or configuration of the present disclosure. Rather, the following description of exemplary embodiments will provide those skilled in the art with an enabling description for implementing one or more exemplary embodiments. Various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the subject matter as set forth in the appended claims.

[0069] In the following description, specific details are given to provide a thorough understanding of the embodiments. However, those skilled in the art will understand that the embodiments can be practiced without these specific details. For example, systems, processes, and other elements in the disclosed subject matter may be shown as components in block diagrams so as not to obscure the embodiments in unnecessary detail. Also, well-known processes, structures, and techniques may be shown without unnecessary detail so as not to obscure the embodiments. Furthermore, like reference numbers and names in the various drawings refer to like elements.

[0070] Each embodiment may also be described as a process, which is depicted as a flowchart, flow diagram, data flow diagram, structure diagram, or block diagram. Although a flowchart may describe operations as a sequential process, many operations may be performed in parallel or simultaneously. The order of operations may also be changed. A process may be terminated when its operations are completed, but the process may include additional steps not discussed or shown. Furthermore, not all operations within a specifically described process need be included in all embodiments. A process may be a method, a function, a procedure, a subroutine, a subprogram, etc. When a process is a function, the termination of the function corresponds to the function returning to the calling function or the main function.

[0071] Furthermore, embodiments of the disclosed subject matter may be implemented, at least in part, manually or automatically. The manual or automatic implementation may be implemented, or at least assisted, by machine, hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented by software, firmware, middleware, or microcode, program code or code segments to perform the necessary tasks may be stored on a machine-readable medium. A processor may perform the necessary tasks.

[0072] The various methods or steps outlined herein may be coded as software executable on one or more processors employing any one of a variety of operating systems or platforms. Furthermore, such software may be written using any of a number of suitable programming languages ​​and / or programming or scripting tools, and compiled as executable machine language code or intermediate code that runs on a framework or virtual machine. Typically, the functionality of the program modules may be combined or distributed in various embodiments as desired.

[0073] Each embodiment is described as a process, which is depicted as a flowchart, flow diagram, data flow diagram, structure diagram, or block diagram. Although a flowchart describes operations as a sequential process, many operations may be performed in parallel or simultaneously. Also, the order of operations may be changed. A process may be terminated when the operations of a process are completed, but the process may include additional steps not discussed or shown. Furthermore, not all operations within a specifically described process need be included in all embodiments. A process may be a method, a function, a procedure, a subroutine, a subprogram, etc. When a process is a function, the termination of the function corresponds to the function returning to the calling function or the main function.

[0074] Furthermore, embodiments of the disclosed subject matter may be implemented, at least in part, manually or automatically. The manual or automatic implementation may be implemented, or at least assisted, by machine, hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented by software, firmware, middleware, or microcode, program code or code segments to perform the necessary tasks may be stored on a machine-readable medium. A processor may perform the necessary tasks.

[0075] Many variations and other embodiments of the present disclosure will suggest themselves to those skilled in the art having the benefit of the teachings presented in the foregoing description and the associated drawings. Moreover, the present disclosure is not limited to the particular embodiments disclosed, and variations and other embodiments are intended to be included within the scope of the appended claims. Furthermore, while the foregoing description and the associated drawings describe exemplary embodiments with reference to certain illustrative combinations of elements and / or functions, different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the appended claims. For example, as set forth in some of the appended claims, combinations of elements and / or functions other than those expressly described above are also contemplated. Although specific terms are used in the present disclosure, these terms are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. An apparatus for performing magnetic refrigeration, comprising: a layered structure formed by coupling an array of Peltier modules and an array of magnetocaloric material (MCM) components, each Peltier module of the plurality of Peltier modules being sandwiched between two MCM components of the plurality of MCM components; a power supply configured to simultaneously supply power to each Peltier module in the array of Peltier modules, wherein current in each powered Peltier module flows in a single direction; a magnetic source configured to apply a spatially uniform magnetic field to the array of MCM components.

2. a first layer of the layered structure being a first MCM component in the array of MCM components; The apparatus of claim 1 , wherein the last layer of the layered structure is the last MCM component in the array of the plurality of MCM components.

3. The apparatus of claim 2 , wherein at least the first MCM component and the last MCM component in the array of MCM components have a porous structure.

4. At least the first MCM component and the last MCM component in the array of MCM components are connected to a cooling unit; The apparatus of claim 2 , wherein the cooling unit includes at least one of a pipe, a working fluid, and a heat exchanger.

5. 3. The apparatus of claim 2, wherein the first MCM component or the last MCM component in the array of MCM components receives cooling air via a fan.

6. a second layer of the layered structure is a first Peltier module; a third layer of the layered structure is a second MCM component; a fourth layer of the layered structure is a second Peltier module; 10. The apparatus of claim 1, wherein the second MCM component is sandwiched between the first Peltier module and the second Peltier module.

7. 10. The apparatus of claim 1, wherein each MCM component of said plurality of MCM components is constructed from a gadolinium alloy.

8. 2. The apparatus of claim 1, wherein the number of MCM components in the array of MCM components is determined based on a required temperature difference between a first MCM component and a last MCM component in the array of MCM components.

9. each Peltier module of the plurality of Peltier modules includes an n-doped semiconductor electrically connected to a p-doped semiconductor; The device of claim 1 , wherein the p-doped semiconductor is arranged in parallel with the n-doped semiconductor.

10. 10. The device of claim 9, wherein the n-doped semiconductor and the p-doped semiconductor are at least one of a silicon-based semiconductor or a bismuth telluride-based semiconductor.

11. 10. The apparatus of claim 1, wherein a thickness of each MCM component in the array of MCM components ranges from 0.1 centimeters (cm) to 1 cm.

12. 10. The apparatus of claim 1, wherein the amount of current supplied to each powered Peltier module is determined based on the number of MCM components selected to perform the magnetic refrigeration and a coefficient of performance associated with the layered structure.

13. 1. A method for magnetic refrigeration, comprising: forming a layered structure by coupling an array of Peltier modules and an array of magnetocaloric material (MCM) components, each Peltier module of the plurality of Peltier modules being sandwiched between two MCM components of the plurality of MCM components; using a power source to simultaneously power each Peltier module in the array of Peltier modules, wherein current in each powered Peltier module flows in a single direction; The method includes applying a spatially uniform magnetic field to the array of MCM components using a magnetic source.

14. a first layer of the layered structure being a first MCM component in the array of MCM components; The method of claim 13 , wherein the last layer of the layered structure is the last MCM component in the array of MCM components.

15. The method of claim 14 , wherein at least the first MCM component and the last MCM component in the array of MCM components have a porous structure.

16. further comprising connecting a cooling unit to at least the first MCM component and the last MCM component in the array of MCM components; The method of claim 14 , wherein the cooling unit includes at least one of a pipe, a working fluid, and a heat exchanger.

17. 15. The method of claim 14, further comprising: the first MCM component or the last MCM component in the array of MCM components receiving cooling air via a fan.

18. a second layer of the layered structure is a first Peltier module; a third layer of the layered structure is a second MCM component; a fourth layer of the layered structure is a second Peltier module; The method of claim 13 , wherein the second MCM component is sandwiched between the first Peltier module and the second Peltier module.

19. 14. The method of claim 13, further comprising determining a number of MCM components in the array of MCM components based on a required temperature difference between a first MCM component and a last MCM component in the array of MCM components.

20. 14. The method of claim 13, further comprising determining the amount of current supplied to each powered Peltier module based on a number of the MCM components selected to perform the magnetic refrigeration and a coefficient of performance associated with the layered structure.

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