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The aim of this study is to identify key factors limiting efficiency of pumped heat energy storage systems and determine some general features of transient behavior of solid state, sensible heat storages. Moreover, it aimed at establishing a feasible approach to transient conjugate heat transfer (CHT) analyses for such applications.

A zero-dimensional analytical model is used to determine the system efficiency sensitivity to efficiency of its components. Analysis of argon gas flow in an exemplary configuration of layered bed thermal energy storage is presented. The analysis incorporates a unsteady reynolds averaged navier stokes model with conjugate heat transfer between gas and solid storage core.

It is established that exergetic efficiency of the heat storage is one of the key factors for the system’s overall performance. Three full cycles of storage charging and discharging having 17 h physical time in total are simulated, with calculation of exergetic efficiency for each of the cycles. From standpoint of the system efficiency, it is concluded that the presented heat storage kind has limited exergetic efficiency because of severe temperature drop at the solid–fluid interface in comparison to granular kind of heat storage devices. From the methodological standpoint, it is concluded that calculating the exergetic efficiency of the heat storage by direct computational fluid dynamics (CFD) analysis requires significant amount of walltime and computational resources.

The paper presents unconventional approach to using standard CFD tools by exploiting numerical diffusion to numerically suppress high-frequency solution oscillations. This strategy grants that the analysis, otherwise requiring impractically long computation walltime, is completed within a practical time.

Public acts of self-criticism in Eastern Europe – a genre cultivated and extorted by the communist parties – did not disappear with the end of communism. In the young democracies of the region self-criticism has become an attempt to diagnose society’s ‘backward’ character and to develop ‘self-correction’ scenarios in order to participate in the Western modernising discourse. On the one hand, conservative and right-wing elites suppose that public acts of self-criticism (performed by politicians, artists or scholars) can endow the vetting procedures of the ancien régime with a sense of social catharsis and retroactive justice. On the other hand, liberal and left-wing intellectuals subject themselves to collective self-reckoning, not only with their choices made in the transition period, but also with the memory of WWII, in order to shape a civil society free of anti-Semitism and intolerance. An analysis based on the discourse-historical approach in critical discourse analysis, Reinhart Koselleck’s historical semantics and Michel Foucault’s notion of discourse, and carried out on the text corpus of selected acts of self-criticism in Poland, aims to diagnose the role these acts had in shaping public discourse on the troublesome past.