18 October >>10am Development of vibration-free sorption-based coolers at University of Twente
Prof. dr. Marcel ter Brake (University of Twente, The Netherlands)
Wednesday 18th October 2017 at 10am
Institut Néel - CNRS Grenoble
Room E424, Building E
25, av. des Martyrs
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Development of vibration-free sorption-based coolers at University of Twente.
The development of sorption-based cryogenic coolers at the University of Twente is presented. These coolers use a thermal compressor of which the operation is based on the cyclic adsorption of a gas at low pressure and desorption at high pressure. Activated carbon is used as the sorber material and the sorption cycle is controlled by heating and cooling of that carbon. The advantage of sorption coolers is the absence of moving parts and, as a result, their vibration-free operation and potentially very long life. In two subsequent ESA-TRP projects we developed and built a 4.5 K helium stage followed by a 14.5 K hydrogen cooler stage. The latter cooler can be used as stand-alone or as a precooling stage for the helium cooler. We recently closed an ESA-CTP (Core Technology Programme) project with the aim to increase the TRL level of this hydrogen cooler from TRL 4 to TRL 5. In the presentation these projects will be discussed, the designs will be presented as well as the experimental test results. Furthermore, an analysis will be presented on a sub-2K JT cooler running with helium-3, precooled at 4 K, and operated by a sorption compressor that is heat sunk at 15 K.
The presentation is closed with a discussion on a sorption-based helium-3 pump that is designed to be incorporated in a closed-cycle dilution refrigerator (CCDR) that is realized by the Néel institute in Grenoble. This CCDR is to be used for future long-lifetime space missions requiring a cooling power of the order of 1 microWatt at typically 50 mK for at least 5 years. A crucial component in this zero-gravity dilution refrigerator is a pump that circulates helium-3 between 5 and 200 mbar. For this purpose, we designed, manufactured and tested a sorption-based circulation pump. Compared to mechanical pumps the advantages are lower input, and also lower mass and less complex interfacing. The latter two advantages result from the fact that the pump is fully integrated with the cold part of the CCDR, whereas the alternative mechanical pumps need to be operated at the 300 K level. The construction of the sorption-based pump and test set-up will be presented as well as the test results.
Contact : Alliance Cryogénie du LANEF