The Elusive Thomson Effect in Thermoelectric Devices. Experimental Investigation from 363 K to 213 K on Various Peltier Modules

Valter Giaretto,Elena Campagnoli

doi:10.3390/met10020291

Abstract

At steady state, in the governing equation of one-stage thermoelectric cooler, the heat resulting from Fourier conduction is balanced by heat generation due to the Joule and Thomson effects inside semiconductors. Since the heat flux observed at the junction of a semiconductor, r pair includes the Peltier effect and the Fourier heat flux caused by both the aforementioned contributions, the Thomson effect is easily masked by the Joule heat, which makes it elusive. With the aim of highlighting the contribution of the Thomson effect, measurements were carried out in the temperature range from 363 K to 213 K on different Peltier modules. The temperature dependence of the Seebeck and Thomson coefficients was evaluated as well as the electrical resistivity, and thermal conductivity of the Peltier modules examined. The results obtained show that the temperature dependence of the thermoelectric properties can reduce the cooling capacity of the Peltier module compared to what is declared in the technical datasheets of the commercial devices. The analyses allow us to conclude that an increase in the Thomson effect could have a positive effect on the performance of the Peltier only if it were possible to reduce the Joule contribution simultaneously.

Highlights

There are many technological areas in which wasted energy can be successfully harvested by thermoelectric devices, such as residential building, automotive sector, and railway rolling stock [1,2,3]
This paper presents the experimental investigations carried out on various commercial Peltier modules over their whole operating temperature range
The results of the tests performed on various commercial Peltier modules, described in the section, make it possible to highlight the temperature dependence of their thermoelectric properties, previous section, make it possible to highlight the temperature dependence of their thermoelectric in particular for the Seebeck coefficient ε, the electric resistivity ρ, and the thermal conductivity λ

Summary

Introduction

There are many technological areas in which wasted energy can be successfully harvested by thermoelectric devices, such as residential building, automotive sector, and railway rolling stock [1,2,3]. To obtain low and stable thermal levels for mimicking the effects induced on the biological tissue by a surgical cryoprobe, single-stage Peltier devices have been assembled in a stack, by feeding each one with proper electrical currents [7,8]. In the latter, the well-known complaint about the poor performance of these devices is of little importance, but the relationship between the feeding current, the cooling capacity, and the minimum temperature reached must be adequately known. Few of these suggest alternative methods on determining the thermoelectric properties, the Thomson effect is commonly not considered in the theoretical approach

Results

Discussion

Conclusion