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EP-4350250-B1 - CRYOCOOLER WITH TRANSIENT THERMAL STORAGE

EP4350250B1EP 4350250 B1EP4350250 B1EP 4350250B1EP-4350250-B1

Inventors

  • ALAHYARI, ABBAS A.
  • KSHIRSAGAR, Parag M.

Dates

Publication Date
20260506
Application Date
20230803

Claims (12)

  1. A cryocooler device (200) comprising: a cryocooler (205) including an input and an output (600), the input forming a cooling path (400), and a first stage (210) that is configured to cool a working fluid in the cooling path; a cooling loop (300) thermally connected to the first stage that transfers heat away from the first stage towards the output of the cryocooler; and at least one thermal energy storage device selectively connectable to the cooling path and the cooling loop, wherein in a first operational mode of the cryocooler device where the at least one thermal energy storage device is connected to the cooling loop the heat to be removed at the input exceeds a cooling capacity of the cryocooler device, and in a second operational mode where the at least one thermal energy storage device is connected to the cooling path the heat to be removed is less than the cooling capacity of the cryocooler and the heat is removed from the at least one thermal energy storage device.
  2. The cryocooler device (200) of claim 1, wherein the thermal energy storage device includes a working fluid selected from the group consisting of Neon, Argon, Methane, Helium, Hydrogen, and Nitrogen.
  3. The cryocooler device (200) of claim 1 or 2, wherein the cryocooler (205) is a Stirling cryocooler, a magnetocaloric cryocooler, pulse tube cryocooler, a helium cryocooler, or a polycold cryocooler.
  4. The cryocooler device (200) of claim 1, 2 or 3, wherein the cryocooler (205) contains at least two stages (210, 220) and at least two cooling loops (300, 340).
  5. The cryocooler device (200) of claim 4, wherein the first cooling loop (300) is configured to transfer heat away from the first stage (210) towards the output (600) connected to the cryocooler (205), wherein the thermal energy storage device is arranged along the cooling path (400) and the first cooling loop (300).
  6. The cryocooler device (200) of claim 4 or 5, wherein the second cooling loop (340) is configured to transfer heat away from the second stage (220) towards the output (600) connected to the cryocooler (205), wherein the thermal energy storage device is arranged along the cooling path (400) and the second cooling loop.
  7. The cryocooler device (200) of any of claims 1 to 6, when dependent on any of claims 1 to 3, wherein the cryocooler (205) contains at least two stages (210, 220), at least two cooling loops (300, 340), and at least two thermal energy storage devices, and when dependent on any of claims 4 to 6, the cryocooler (205) further contains at least two thermal energy storage devices.
  8. The cryocooler device (200) of claim 7, wherein the first cooling loop (300) is configured to transfer heat away from the first stage (210) towards the output (600) connected to the cryocooler (205), wherein the first thermal energy storage device is arranged along the cooling path (400) and the first cooling loop (300), wherein the second cooling loop (340) transfers heat away from the second stage (220) towards the output connected to the cryocooler, wherein the second thermal energy storage device is arranged along the cooling path and the second cooling loop.
  9. An aircraft system comprising: an electric engine (105); and a cryocooler device (200) according to any preceding claim in thermal communication with the electric engine that cools the electric engine.
  10. The aircraft system of claim 9, wherein the cryocooler (205) contains multiple stages (210, 220, 230), multiple cooling loops (300, 340), and multiple thermal energy storage devices.
  11. The aircraft system of claim 10, wherein the first cooling loop (300) is configured to transfer heat away from the first stage (210) towards a thermal sink connected to the cryocooler, wherein the first thermal energy storage device is arranged along the cooling path (400) and the first cooling loop, wherein the second cooling loop (340) transfers heat away from the second stage (220) towards a thermal sink connected to the cryocooler, wherein the second thermal energy storage device is arranged along the cooling path and the second cooling loop.
  12. A method for cooling an engine (105), comprising: providing an electric engine; providing a cryocooler device (200) according to any of claims 1 to 8 in thermal communication with the electric engine, that cools the electric engine, operating the cryocooler device to increase the relative cooling power by providing the working fluid to the first stage through the cooling path, when the thermal energy storage device is connected to the cooling loop, operating the cryocooler to decrease the relative cooling power by providing the working fluid to the first stage and the thermal energy storage device through the cooling path, when the thermal energy storage device is connected to the cooling path.

Description

TECHNICAL FIELD This invention relates to cooling electric engines and, more particularly, to a cryocooling device that includes a device for cooling energy when the cryocooling device is operating below peak operating levels. BACKGROUND Some components of an aircraft such as superconducting electric motors and drives, may need to be cooled to cryogenic temperatures of about 77 °K or less to function properly. A number of approaches are available including thermal contact to liquefied gases and cryogenic refrigerators, usually termed cryocoolers. One type of cryocooler functions by the expansion of a gas, which absorbs heat from the surroundings. Intermediate temperatures in the cooling component may be reached using a single-stage expansion. To reach colder temperatures, such as about 40° K or less, a multiple-stage expansion cooler may be used. Another type of cryocooler is a magnetocaloric cooler. These cryocoolers achieve the low temperatures in several refrigeration stages through adiabatic magnetization and demagnetization of certain magnetocaloric material. The cryocooler must be capable of maintaining the operating temperature for the component being cooled, regardless of this variation in heat loading and the temporary high levels. While it handles this variation in heat loading, the cryocooler desirably would draw a roughly constant power level, so that there are no wide swings in the power requirements that would necessitate designing the power source to accommodate the variation. One possible solution to the problem is to size the cryocooler to handle the maximum possible heat loading. This solution has the drawback that the cryocooler is built larger than necessary for steady-state conditions, adding unnecessarily to the size and weight of an aircraft. EP 1498670 A2 discloses a cooling system for providing cryogenic cooling fluid to an apparatus comprising a re-circulation device, a passive cold storage device having a porous matrix of material which directly contacts the cryogenic cooling fluid as the cryogenic cooling fluid passes through the passive cold storage device, a first portion of a fluid communication feed line fluidly connecting the re-circulation device to the passive cold storage device, a second portion of a fluid communication feed line fluidly connecting the passive cold storage device to the apparatus for communicating cryogenic cooling fluid to the apparatus, and a fluid communication return line fluidly connecting the apparatus to the re-circulation device. BRIEF SUMMARY According to a first aspect of the invention a cryocooler device is provided as recited in claim 1. In addition to one or more of the features described above, the device can include a working fluid selected from the group consisting of Neon, Argon, Methane, Helium, Hydrogen, and Nitrogen. In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the cryocooler can be a Stirling cryocooler, a magnetocaloric cryocooler, pulse tube cryocooler, a helium cryocooler, or a polycold cryocooler. In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the cryocooler can contain at least two stages and at least two cooling loops. In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the cryocooler device can contain a first cooling loop of the cryocooler that is configured to transfer heat away from the first stage towards the output connected to the cryocooler. The device also includes a thermal energy storage device, which is arranged along the cooling path and the first cooling loop. In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the device contains a second cooling loop that is configured to transfer heat away from the second stage towards the output connected to the cryocooler. The device also includes a thermal energy storage device, which is arranged along the cooling path and the second cooling loop. In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the cryocooler can contain at least two stages, at least two cooling loops, and at least two thermal energy storage devices. In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the cryocooler device may contain a first cooling loop that is configured to transfer heat away from the first stage towards the output connected to the cryocooler. The device also contains a first thermal energy storage device, that is arranged along the cooling path and the first cooling loop. The second cooling loop transfers heat away from the second stage towards the output connected to the cryocooler. The device also contains a second thermal energy storage device, that is arranged along the cooling p