Causality in thermoelectric systems: Insights from block diagrams

TL;DR

This paper investigates the causality constraints in thermoelectric systems, especially refrigerators, highlighting how heat conduction alone cannot ensure causal behavior, with insights derived from block diagram analysis.

Contribution

It introduces a block diagram framework to analyze causality in thermoelectric systems and clarifies the role of dissipation sources in system causality.

Findings

Heat conduction alone does not ensure causality.

Dissipation sources significantly impact system causality.

Block diagram analysis provides new insights into thermoelectric system behavior.

Abstract

While Carnot's model engines demonstrate ideal performances regarding conversion efficiency, they cannot be actually used as energy converters since they are non causal systems. Such an unphysical behavior indeed restrains the working conditions to a single point where, in the case of a refrigerator (generator), the cooling power (output power) vanishes. Focusing on the example of a thermoelectric refrigerator, we study the impact of different dissipation sources on the causality of such systems. Basing our analysis on the block diagram description of this system, we discuss particularly the fact that heat conduction cannot ensure causality.