EXPERIMENTAL STUDIES ON A SINGLE STAGE STIRLING TYPE PULSE TUBE CRYOCOOLER DRIVEN BY OIL‐LUBRICATED COMPRESSOR

Because lubricating oil for moving parts is not allowed to go into the pulse tube cryocooler, Stirling type pulse tube cryocoolers are generally driven by oil‐free compressors although oil‐lubricated compressors are much cheaper and facile. Recently, it was proposed that an acoustic transparent and oil blocking diaphragm could be employed to separate the compressor and the cryocooler. Thus, the cryocooler can be driven by oil‐lubricated compressors. In this paper, a pulse tube cryocooler is designed to match a crankcase compressor. Although the efficiency of the crankcase compressor is lower compared with the oil‐free linear compressor, the crankcase compressor can easily work at lower frequency which results in higher efficiency for the cryocooler. So the relative high performance of the whole system can be maintained. In this system, the cryocooler delivers 28.5 W of cooling at 80 K with 680 W of electrical input power and operates at 15 Hz. The corresponding Carnot efficiency is 11.52%.