We employed numerical analysis methods to assess time between failures for microcryogenic gas systems at the design stage, taking into account various factors, including structural parameters. We suggest using multi-factor heat, gas and fluid dynamics analysis, based on integration of accumulated experience in experimental investigations and numerical modelling. We provide an example of applying this multi-factor heat, gas and heat dynamics analysis to analysing units of microcryogenic gas systems. We conducted three-dimensional numerical modelling of structure and fluid dynamics in a honeycomb regenerator as the primary risk-accumulating unit. We compared the results of numerically investigating the drag in the regenerator we modelled as a function of the Reynolds number to the results of computations based on foreign researchers’ correlation dependences, which showed a high degree of convergence with Tanaka’s and Blase’s dependencies. This comparison forms the basis for using the model supplied in the mathematical model for further computations.