Thermal Energy Storage Demonstration Unit for Vuilleumier Cryogenic Cooler (Hi-Cap Unit Number 2). Addendum.

Abstract : A second thermal energy unit for the High Capacity (Hi-Cap) Vuilleumier Cryogenic Cooler was built and tested. Incorporated into this unit were several design improvements consisting of the addition of a conduction heat transfer barrier between the radiation heat shield insulation and the mounting flange, modification of the O-ring seal of the insulation container, moving the hot cylinder-mounting flange interface, and changing the instrumentation. All design changes proved to be beneficial. The thermal losses that can be attributed to heat transfer through the insulation were lowered by about 8W from those of the first Hi-Cap TES unit. The inclusion of the teminal ring into the flange and separating the flange from the hot cylinder resulted in a substantial cost saving in material and machining of the components. The three, 1/16-inch diameter Inconel sheathed K calibration thermocouples performed consistently during the entire test period. The prime concern has been the discharge characteristic of the TES unit. Test data evaluation has indicated that the charging characteristic of the TES unit should be further investigated to obtain necessary information which will be required for the integration of the TES unit with the cryogenic cooler. (Author)