English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Low-temperature-differential (LTD) Stirling heat engines are able to operatewith a small temperature difference between low-temperature heat reservoirsthat exist in our daily lives, and thus they are considered to be an importantsustainable energy technology. The author recently proposed a nonlineardynamics model of an LTD kinematic Stirling heat engine to study the rotationalmechanism of the engine [Y. Izumida, EPL \textbf{121}, 50004 (2018)]. Thispaper presents our study of the nonequilibrium thermodynamics analysis of thisengine model, where a load torque against which the engine does work isintroduced. We demonstrate that the engine's rotational state is in aquasi-linear response regime where the thermodynamic fluxes show a lineardependency on the thermodynamic forces. Significantly, it is found that theresponse coefficients of the quasi-linear relations are symmetric, which issimilar to Onsager symmetry in linear irreversible thermodynamics. Based onthese relations, we formulate the maximum efficiency of the engine. We alsoelucidate that the symmetry of the quasi-linear response coefficients emergesby reflecting the (anti-)reciprocity of the Onsager kinetic coefficientsidentified for the relaxation dynamics of the engine in the vicinity of anequilibrium state. We expect that the present study paves the way fordeveloping nonequilibrium thermodynamics of autonomous heat engines describedas a nonlinear dynamical system.

Quasi-linear irreversible thermodynamics of a low-temperature-differential kinematic Stirling heat engine