Cryogenic Engineering and Vacuum Technology Research Summary, Department of Engineering Science, University of Oxford 1.7 Cryogenic Engineering and Vacuum Technology Overview Activities are focused on Stirling cycle machines to produce refrigeration for a wide range of applications in space, defence and civil commercial environments. The emphasis is on oil free systems of exceptional reliability with other applications in external combustion engines for small scale power generation, and linear compressors for medical, scientific and refrigeration purposes.
Most applications require high efficiency and very high reliability.
Over the past ten years, we have developed a range of such machines using the Stirling cycle with reciprocating pistons and displacers. The reciprocating parts are mounted on spring suspension systems allowing all the dynamic seals to be of the clearance type. The cycle is driven by a linear motor using a permanent magnet. Machines have been built to give from 80mW to 100W of cooling power at temperatures from 65K upwards. Licence agreements are in place with a number of companies for a range of applications.