Remote cooling circulator with cold valves

A fluid loop can be effective for cooling some distance from a pulse tube cooler or in applications that require vibration isolation from the cooled object. Space pulse tube coolers are very efficient, but like all regenerative high frequency Stirling and pulse tube coolers, the cold head needs to be located near the compressor in order to minimize the input power to the cooler. To provide the directional gas flow from the oscillating flow pulse tube cooler we added cold reed valves to the pulse tube cold block of our flight proven high efficiency cooler (HEC) so that cold gas could be circulated without the need for an additional circulation pump and additional heat exchangers to cool the gas. In this test an improved smaller cold valve than that previously reported was installed and the remote cooling and the parasitic heat loads were measured. The measurements are compared to those of our previously reported cold valve tests as well as warm reed valve tests that used a second circulator compressor and recuperative heat exchanger. The large improvement in remote cooling power relative to the previous cold valve tests will be described.