Magnetic refrigerator
First Claim
1. A thermal diode module for a magnetic refrigerator comprising:
- a sealed container having an evaporator end and a condenser end;
a heat-transfer fluid disposed in said container;
an array of magnetocaloric material subject to a reversible increase in temperature upon being exposed to a magnetic field, said array located within said container at said evaporator end and said material being in the form of a porous matrix whereby said material may come into direct thermal contact with said heat-transfer fluid during a high-temperature portion of an operating cycle;
a condensing surface located at said condenser end; and
means for returning condensed fluid to said evaporator end.
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Accused Products
Abstract
A magnetic refrigeration system uses high-temperature side thermal diode modules with magnetocaloric material placed inside of hermetically sealed module containers. The material in the form of a porous matrix. The material comes into direct thermal contact with or is submerged in a hest transfer fluid, and a radical increase in heat transfer is obtained due to large surface area and pores in the material, which serve as nucleation sites and develop thin meniscus evaporating layers. These modules also contain special condensing surfaces and a means for return of condensed fluid to the evaporator. Various combinations with low-temperature side modules are also disclosed. A refrigeration system using the modules includes a rotatable disk on which a plurality of modules disposed radially on the disk are carried, and the disk is rotated in proximity to a magnetic field generator so that the material in the modules is intermittently magnetized and thereby heated. Sets of modules may be arranged to provide staging, thus producing refrigeration over a wide temperature range and enabling use of newer, high-performance materials which are glassy and difficult or impossible to fabricate into conventional heat-exchanger component shapes.
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Citations
21 Claims
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1. A thermal diode module for a magnetic refrigerator comprising:
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a sealed container having an evaporator end and a condenser end;
a heat-transfer fluid disposed in said container;
an array of magnetocaloric material subject to a reversible increase in temperature upon being exposed to a magnetic field, said array located within said container at said evaporator end and said material being in the form of a porous matrix whereby said material may come into direct thermal contact with said heat-transfer fluid during a high-temperature portion of an operating cycle;
a condensing surface located at said condenser end; and
means for returning condensed fluid to said evaporator end.- View Dependent Claims (2, 3, 4, 5)
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6. A refrigeration module comprising;
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a high-temperature side thermal diode module comprising;
a first sealed container having an evaporator end and a condenser end;
a heat-transfer fluid disposed in said container;
an array comprised of magnetocaloric material subject to a reversible increase in temperature upon being exposed to a magnetic field, said array located within said container at said evaporator end and said material being in the form of a porous matrix whereby said material may come into direct thermal contact with said heat-transfer fluid during a high-temperature portion of an operating cycle;
a condensing surface located at said condenser end; and
means for returning condensed fluid to said evaporator end; and
a low-temperature side thermal diode module comprising;
a second sealed container having an evaporator end, a condenser end, a heat-transfer fluid disposed therein and a means for returning said heat-transfer fluid from said condenser end of said low-temperature thermal diode module to said evaporator end thereof; and
the said evaporator end of said high-temperature module being disposed in heat-transferring relation to said condenser end of said low temperature module. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A magnetic refrigerator comprising:
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a magnetic field generator;
at least one refrigeration module comprising a high-temperature side thermal diode module comprising a sealed container, said container having an evaporator end and a condenser end, a heat-transfer fluid and means for returning condensed heat-transfer fluid from said condenser end back to said evaporator end;
an array of magnetocaloric material subject to a reversible increase in temperature upon being exposed to a magnetic field, said array located within said container at said evaporator end and said material being in the form of a porous matrix, whereby said material may come into direct thermal contact with said heat transfer fluid during a high-temperature portion of an operating cycle;
a low-temperature side thermal diode module comprising a sealed container having an evaporator end, a condenser end, a heat transfer fluid disposed therein and means for returning condensed heat-transfer fluid back to said evaporator end;
the said evaporator end of said high-temperature module being disposed in thermal contact with the said condenser end of the said low-temperature module;
a heat sink; and
means for intermittently applying a magnetic field produced by said generator to said material; and
means for providing heat flow from an object to be cooled to the said material when the said material is demagnetized. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A magnetic refrigerator module comprising:
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a series of sets of thermal diode modules, each said set having a high-temperature side module and a low-temperature side module with a selected magnetocaloric material disposed at an evaporator end of the high-temperature module of each said set and a heat-transfer fluid carried in each said module;
said sets being staged with the high side of a first module thermally connected to the low side of a succeeding module, repeated progressively over a series;
a specific magnetocaloric material selected to provide a first, low effective temperature range for the first set and progressively higher effective temperature ranges for successive sets; and
a specific heat-transfer fluid being selected for its operability at the temperature employed in a specific said set.
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Specification