Rotary-Reciprocating Cryogenic Refrigeration Systems Studies. Part I. Analysis.
Abstract:
The report describes the results of several analyses conducted on rotary-reciprocating cryogenic refrigeration systems to be used on long-term space missions. A computer program which was developed under the contract is described. The program will balance a thermodynamic flowsheet and design a rotary reciprocating refrigerator to meet performance requirements which are specified as input variables to the program. The program will select the appropriate thermodynamic cycle based upon the number of loads specified and the load temperature levels. Four thermodynamic cycles, all derivatives of the reversed Brayton and Claude cycle, are contained in the program. A preliminary functional design of power conditioning equipment for rotary-reciprocating refrigerators is also described. It is concluded that the power conditioning equipment design presented is capable of very high reliability and that the efficiency can exceed 95 for some source voltages. The results of an analysis of thermal losses in gas springs for rotary-reciprocating refrigerators are also presented. It is concluded that irreversible heat transfer is a significant loss mechanism in gas springs. An analytical expression for the thermal loss is derived. Finally, the results of a study to estimate the input power, weight, and size of some selected rotary-reciprocating cryogenic refrigerators which develop useful refrigeration simultaneously at two temperature levels are presented. Author