Active cooling plans by benbenzhou


									       Active Coolers
for cooling Infrared Detector
      satellite payloads

     Stirling Cooler   Presentation By
                        Milind B Naik
                       TIFR, MUMBAI
                     Types of coolers

• Passive Coolers
     • Radiators
     • Stored Cryogens

• Active Coolers
     •   Stirling cycle (this presentation covers this cooler )
     •   Pulse tube
     •   Joule-Thompson
     •   Brayton
     •   Adiabatic Demagnetization
     •   3He coolers
     •   Optical cooling
     •   Peltier effect coolers
• Passive Coolers
    • Radiators
       – Radiators are panels radiating heat according to Stefan's Law
       – extremely high reliability
       – low mass and a lifetime limited only by surface contamination
         and degradation
       – limitations on the heat load and temperature (typically in the
         milliwatt range at 70K )
       – Multiple stages are often used
    • Stored cryogens.
       – Dewars containing a cryogen such as liquid helium or solid
       – excellent temperature stability with no exported vibrations
       – substantially increases the launch mass of the vehicle
       – limit the lifetime of the mission to the amount of cryogen stored
• Active Coolers
    • Stirling cycle.
        – These coolers are based on causing a working gas to undergo
          a Stirling cycle which consists of 2 constant volume processes
          and two isothermal processes.
        – Devices consist of a compressor pump and a displacer unit with
          a regenerative heat exchanger, known as a `regenerator'.
        – Stirling cycle coolers were the first active cooler to be used
          successfully in space and have proved to be reliable and
        – Recent years have seen the development of two-stage devices
          which extend the lower temperature range from 60-80K to 15-
Advantages/disadvantages of different
     types of cooler technology
Some examples of missions using
        active coolers

  •Missions are listed as vehicle/instrument.
  •Design lifetime has been quoted if the instrument is yet to be launched
           or failed due to another component.
  •Excluding electronics.
  •STS/BETSE was a technology demonstrator.
  •UARS/ISAMS figures per cooler running at 83% stroke.
example of missions using
     active coolers
Typical cryocooler to be used for satellite payload


                                      COLD FINGER

   ( ISRAEL)
Set of cold-finger available for Cryocooler
Working of stirling cryocooler
 Hot side (with heat sink)   Cold side (cold finger)

                                                                  Hot side

                                                   Cold side (cold finger)
Working of stirling cryocooler
Test-dewar for cryocooler testing


Test-dewar for cryocooler testing

                             Temperature Sensor

• Various processes involved for testing
  Stirling cryocooler
       – Design, development of test-dewar with vacuum seal,
         feedthrough wires, optical window, temperature sensor
         integration with cold-finger etc.
       – Assembly , evacuation of test-dewarCrcycooler assembly
       – Crycooler Fill and purge with Helium
       – Various leak tests
       – Functional tests
       – Calibrations
       – Others.
Thanks …

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