Cryocoolers Applications
Sunpower’s Stirling cryocoolers are superior in efficiency and power density; more cooling, smaller package, and less energy. Following are examples of fields of use that have benefited from the CryoTel® solution:
Transport freezers: GLACIER
The University of Alabama, Birmingham designed and fabricated freezers to be used on the Space Shuttle and the International Space Station. The General Laboratory Active Cryogenic International Space Station (ISS) Experiment Refrigerator (GLACIER) is a rear-breathing or water-cooled cryogenic freezer that provides cryogenic transportation and preservation of samples requiring temperatures between +4°C and -160°C. The cold volume of the unit has a generic design that allows multiple types of science samples requiring cryogenic thermal storage to use the GLACIER. For more information go here: http://www.nasa.gov/mission_pages/station/research/experiments/GLACIER.html
Sunpower’s CryoTel-CT® cryocoolers provided the energy efficiency and power density that was necessary to ensure the viability of the freezer design and its ability to meet the strict space and power consumption requirements that were specified by NASA.
Germanium detectors: RHESSI
NASA Goddard Space Flight Center chose Sunpower's cryocooler technology and expertise to provide the critical cryogenic cooling for the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). RHESSI's primary mission is to explore the basic physics of particle acceleration and explosive energy release in solar flares. Sunpower's M77 cryocooler (predecessor to the CryoTel® line) was chosen for it's efficiency, energy density, and proven reliability. Since launch in February of 2002, the M77 cryocooler has provided continuous cooling for the mission critical instrumentation. For more information go here, http://hesperia.gsfc.nasa.gov/hessi/index.html
Radio telescopes: MeerKAT
Sunpower’s cryocoolers have found a home in the expanding field of radio telescopes. The Square Kilometer Array (SKA) project in South Africa is a good example: South Africa is building the Karoo Array Telescope (MeerKAT) which is a precursor instrument for the SKA, but will in its own right be amongst the largest and most powerful telescopes in the world. MeerKAT will develop technologies appropriate to the SKA, including the use of composite, one-piece reflectors, single-pixel wideband receivers, low-cost, high-reliability cryogenic systems, and reconfigurable digital processing systems. For more information go here, http://www.ska.ac.za/meerkat/specsci.php. Sunpower coolers have been prototyped on KAT7 (MeerKAT prototype array) and will be considered as one of the options for cooling receivers on MeerKAT.
High value bio-processing: ATMI – Integrity™ LevMixer®
Sunpower's unique Stirling cryocooler technology became the enabler for an innovative product idea that has become a solution for a long-standing problem in the biological processing industry: mixing high value and/or dangerous compounds without allowing contaminants in or out of the compound container.
The mixing technology of the IntegrityTM LevMixerTM system from ATMI, Inc. is based on non-contact magnetic coupling between conventional permanent magnets in the impeller and superconducting material in the drive. Superconducting material has the ability to trap the magnetic field (Meissner Effect) generated by the permanent magnets and "lock the magnetic field in memory" in an equilibrium position. The trapped magnetic field behaves like mechanical springs; if the magnet is moved up, down or sideways by outside forces (e.g., gravity or angular torque) it will tend to be pulled back to an equilibrium position. The peculiar nature of magnet-superconductor interaction ties the two bodies together resulting in a very stable mechanical couple with finite equilibrium separation. The magnet-superconductor couple is the basis for a revolutionary design of the non-contact magnetic levitation mixer.
The Cryogenic temperatures (approx. -200° C) required for the superconducting material are achieved by an internal Stirling cycle cryocooler.
For more information go here: http://www.atmi.com/lifesciences/products/mixers/
Germanium radiation detectors: Canberra Cryo-Cycle™ Cryostat
The CANBERRA Cryo-Cycle™ Cryostat is a revolutionary innovation in the field of cryogenically cooled radiation detectors. This product is described as a "hybrid" cryostat because it utilizes both conventional liquid nitrogen and electric cooling. This arrangement, whereby the built-in cryocooler condenses the boil-off gas from an LN2 reservoir, provides the convenience of electric cooling and the reliability of liquid nitrogen cooling, something never seen before in this field. This capability overcomes one of the most common complaints against conventional electrically powered detector coolers which is loss of cooling during a power failure.
With the Cryo-Cycle™ Cryostat the LN2 supply keeps the detector cold for up to one week in case of power failure. There is no interruption of cooling. Because it is equipped with the Stirling cryocooler, the Cryo-Cycle Cryostat will even make LN2 from bottled nitrogen should no LN2 be available.
The Cryo-Cycle™ Cryostat utilizes a highly efficient and compact long-life Stirling cryocooler. The cryocooler is integrated with a 22 liter LN2 Dewar assembly. The power supply and power controller for the Stirling cooler are incorporated into the cryostat assembly. No external hardware, hoses, or cables are required. The Cryo-Cycle Cryostat simply plugs into an ac (90-240 V, 50-60 Hz) power outlet for operation. The Stirling cryocooler used in the Cryo-Cycle™ Cryostat is derived from a long-life design that was developed for space experiments. The cooler, which uses a non-flammable refrigerant is hermetically sealed so there is no need for replenishment or maintenance. Unlike some Stirling cryocoolers the cooler used in the Cryo-Cycle™ Cryostat is designed and built to prevent contact between mating parts in the integral compressor/cold head, virtually eliminating wear.
For more information about Cryo-Cycle™ Cryostat go here: http://www.canberra.com/products/438025.asp