Improved Thermoelectric Cooling Based on the Thomson Effect

TL;DR

This paper introduces Thomson coolers, a new thermoelectric cooling approach that maintains self-compatibility across the device, potentially doubling the cooling capacity of traditional Peltier coolers and enabling cryogenic temperatures.

Contribution

It presents a theoretical analysis of Thomson coolers, showing they outperform traditional Peltier coolers by maintaining self-compatibility and requiring an exponentially rising Seebeck coefficient.

Findings

Thomson coolers can achieve about twice the maximum temperature drop of Peltier coolers with similar zT.

Self-compatibility enhances thermoelectric performance across the device.

Thomson coolers could enable solid-state cooling down to cryogenic temperatures.

Abstract

Traditional thermoelectric Peltier coolers exhibit a cooling limit which is primarily determined by the figure of merit, zT. Rather than a fundamental thermodynamic limit, this bound can be traced to the difficulty of maintaining thermoelectric compatibility. Self-compatibility locally maximizes the cooler's coefficient of performance for a given zT and can be achieved by adjusting the relative ratio of the thermoelectric transport properties that make up zT. In this study, we investigate the theoretical performance of thermoelectric coolers that maintain self-compatibility across the device. We find such a device behaves very differently from a Peltier cooler, and term self-compatible coolers "Thomson coolers" when the Fourier heat divergence is dominated by the Thomson, as opposed to the Joule, term. A Thomson cooler requires an exponentially rising Seebeck coefficient with increasing temperature, while traditional Peltier coolers, such as those used commercially, have comparatively minimal change in Seebeck coefficient with temperature. When reasonable material property bounds are placed on the thermoelectric leg, the Thomson cooler is predicted to achieve approximately twice the maximum temperature drop of a traditional Peltier cooler with equivalent figure of merit (zT). We anticipate the development of Thomson coolers will ultimately lead to solid state cooling to cryogenic temperatures.