Long-term effects of power quality and power cycling on thermoelectric module performance

Thermoelectric (TE) modules used in a heat pumping mode are increasingly being used for various applications involving heating and cooling. As their use becomes more prevalent and extends to lower cost applications using inexpensive commodity power supplies, it is important to characterize the long-term effects of power cycling and power quality on their performance. Two power supplies were evaluated with different levels of periodic and random deviations (PARD) from ideal DC power. This paper presents the results of an accelerated aging experimental study on intermittent power cycling of TE modules over the span of 5 actual months with each power supply. TE performance metrics that were monitored at specific time intervals are the AC resistance and figure of merit. The applied voltage, power consumption, TE hot and cold side temperatures and air temperatures were continuously measured. The experimental results indicate that the low-quality power supply quality had only a minor influence on properties and integrity of the TE modules, and is suitable for applications requiring intermittent use without a substantial reduction in performance.