Perturbation Methods for Real-Time In Situ Evaluation of Hot-Side Thermal Resistances in Thermoelectric Energy Recovery Systems

摘要

Thermoelectric (TE) power systems in high-temperature industrial, transportation, and military energy systems require high-performance hot-side and cold-side heat transfer to provide the critical temperature differential and transfer the required thermal energy to create the power output. Hot- and cold-side heat transfer performance is typically characterized by the hot-side and cold-side thermal resistance, R (h,th) and R (c,th), respectively. This heat transfer performance determines the hot-side temperature, T (h), and cold-side temperature, T (c), conditions when operating in energy recovery environments with available temperature differentials characterized by an external driving temperature, T (src), and ambient temperature, T (amb). It is crucial to monitor and track the hot-side thermal performance at all times during TE energy recovery system operation, thereby allowing one to track the system "health," predict future expected system performance, and anticipate/prevent system failures. This paper describes the use of a perturbation methodology and a direct coupling between the TE current, voltage, and hot-side energy flow to extract a real-time in situ evaluation of hot-side thermal resistances. External measurable TE parameters, either system current or T (src), can be perturbed during system operation, and the resulting TE system response can then be coupled mathematically to the hot-side thermal transfer performance (i.e., thermal resistance). This paper discusses the mathematical formalism of this technique, and TE module experimental data showing successful application of real-time current perturbation. This technique provides a pathway for developing faster, real-time system monitoring and diagnostics to alleviate system performance degradation, or prevent system damage from dramatic changes in hot-side thermal transfer conditions in industrial, transportation, and spacecraft TE power systems.