REFRIGERATION SYSTEM INCLUDING MICRO COMPRESSOR-EXPANDER THERMAL UNITS
First Claim
1. An active gas regenerative refrigerator, comprising:
- a compressor-expander unit, including;
a main cylinder having first and second cylinder ends and a central cylinder region between the first and second cylinder ends;
a first quantity of working fluid positioned in the first cylinder end;
a second quantity of working fluid positioned in the second cylinder end;
a drive piston positioned inside the main cylinder and having first and second piston ends and a central piston region, the first piston end having a diameter that is less than an inside diameter of the first cylinder end such that when the drive piston is moved to a first extreme, the first mass of working fluid is compressed into a first radial gap formed between a radial surface of the first piston end and an inner radial face of the first cylinder end, the second piston end having a diameter that is less than an inside diameter of the second cylinder end such that when the drive piston is moved to a second extreme, the second mass of working fluid is compressed into a second radial gap formed between a radial surface of the second piston end and an inner radial face of the second cylinder end, wherein the drive piston includes a plurality of permanent magnets arranged in the central piston region with poles aligned axially with the drive piston and in alternating polar orientation such that adjacent magnets are positioned with like poles facing each other;
a seal positioned in the central cylinder region of the main cylinder between an inner face of the main cylinder and the drive piston, configured to permit the drive piston to move axially relative to the main cylinder between the first and second extremes while substantially preventing passage of either of the first or second quantities of working fluid between the first cylinder end and the second cylinder end; and
a piston drive mechanism configured to couple with the drive piston via transverse magnetic flux regions formed by the plurality of permanent magnets, wherein the piston drive mechanism includes;
an electromagnetic coil extending around the central cylinder region, the electromagnetic coil being configured to produce a magnetic field and to couple thereby with the transverse magnetic flux regions of the plurality of permanent magnets.
1 Assignment
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Accused Products
Abstract
An active gas regenerative refrigerator includes a plurality of compressor-expander units, each having a hermetic cylinder with a drive piston configured to be driven reciprocally therein, and a quantity of working fluid in each end of the cylinder. A piston seal in a central portion of the cylinder prevents passage of the working fluid between ends of the cylinder. Movement of the piston to a first extreme results in radial compression of one of the quantities of working fluid in a cylindrical gap formed between one end of the piston and an inner surface of the cylinder, while the other quantity is expanded in the opposite end of the cylinder. The piston includes a plurality of magnets arranged in pairs, with magnets of each pair positioned with like-poles facing each other. A piston drive is configured to couple with transverse magnetic flux regions formed by the magnets.
47 Citations
17 Claims
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1. An active gas regenerative refrigerator, comprising:
a compressor-expander unit, including; a main cylinder having first and second cylinder ends and a central cylinder region between the first and second cylinder ends; a first quantity of working fluid positioned in the first cylinder end; a second quantity of working fluid positioned in the second cylinder end; a drive piston positioned inside the main cylinder and having first and second piston ends and a central piston region, the first piston end having a diameter that is less than an inside diameter of the first cylinder end such that when the drive piston is moved to a first extreme, the first mass of working fluid is compressed into a first radial gap formed between a radial surface of the first piston end and an inner radial face of the first cylinder end, the second piston end having a diameter that is less than an inside diameter of the second cylinder end such that when the drive piston is moved to a second extreme, the second mass of working fluid is compressed into a second radial gap formed between a radial surface of the second piston end and an inner radial face of the second cylinder end, wherein the drive piston includes a plurality of permanent magnets arranged in the central piston region with poles aligned axially with the drive piston and in alternating polar orientation such that adjacent magnets are positioned with like poles facing each other; a seal positioned in the central cylinder region of the main cylinder between an inner face of the main cylinder and the drive piston, configured to permit the drive piston to move axially relative to the main cylinder between the first and second extremes while substantially preventing passage of either of the first or second quantities of working fluid between the first cylinder end and the second cylinder end; and a piston drive mechanism configured to couple with the drive piston via transverse magnetic flux regions formed by the plurality of permanent magnets, wherein the piston drive mechanism includes; an electromagnetic coil extending around the central cylinder region, the electromagnetic coil being configured to produce a magnetic field and to couple thereby with the transverse magnetic flux regions of the plurality of permanent magnets. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of operation, comprising:
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compressing first quantities of working fluid into respective first cylindrical gaps defined by first ends of ones of a plurality of drive pistons and inner surfaces of first ends of respective ones of a plurality of sealed cylinders, and simultaneously expanding second quantities of working fluid positioned in respective second ends of the plurality of sealed cylinders, by moving each of the plurality of drive pistons toward the first ends of respective ones of the plurality of sealed cylinders; transmitting thermal energy from the first quantities of working fluid in the first cylindrical gaps to a first flow of heat transfer fluid by passing the first flow of heat transfer fluid over the first ends of the sealed cylinders, and simultaneously transmitting thermal energy from a second flow of heat transfer fluid to the second quantities of working fluid by passing the second flow of heat transfer fluid over the second ends of the sealed cylinders; compressing the second quantities of working fluid into respective second cylindrical gaps defined by second ends of ones of the plurality of drive pistons and inner surfaces of the second ends of respective ones of the plurality of sealed cylinders, and simultaneously expanding the first quantities of working fluid positioned in the respective first ends of the plurality of sealed cylinders, by moving each of the plurality of drive pistons toward the second ends of the respective ones of the plurality of sealed cylinders; and transmitting thermal energy from the second quantities of working fluid in the second cylindrical gaps to a third flow of heat transfer fluid by passing the third flow of heat transfer fluid over the second ends of the sealed cylinders, and simultaneously transmitting thermal energy from a fourth flow of heat transfer fluid to the first quantities of working fluid by passing the fourth flow of heat transfer fluid over the first ends of the sealed cylinders; and applying a motive force to each of the plurality of drive pistons via regions of transverse magnetic flux; wherein each of the plurality of drive pistons has coupled thereto a respective plurality of permanent magnets with poles arranged in alternating polar orientation such that adjacent magnets are positioned with like poles facing each other, and wherein the moving each of the plurality of drive pistons toward the first ends of respective ones of the plurality of sealed cylinders comprises applying a motive force to each of the plurality of drive pistons via regions of transverse magnetic flux supported by the respective plurality of permanent magnets; and wherein each of the plurality of sealed cylinders has, arranged concentrically thereto, a respective electromagnetic coil arranged to magnetically couple to the respective plurality of magnets via the regions of transverse magnetic flux, and wherein the applying a motive force to each of the plurality of drive pistons comprises driving electrical current through each respective one of a plurality of the electromagnetic coils. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification