Optimized Thermoelectric Module-Heat Sink Assemblies for Precision Temperature Control

Abstract

Robust precision temperature control of heat-dissipating photonics components is achieved by mounting them on thermoelectric modules (TEMs), which are in turn mounted on heat sinks. However, the power consumption of such TEMs is high. Indeed, it may exceed that of the component. This problem is exacerbated when the ambient temperature and/or component heat load vary as is normally the case. In the usual packaging configuration, a TEM is mounted on an air-cooled heat sink of specified thermal resistance. However, heat sinks of negligible thermal resistance minimize TEM power for sufficiently high ambient temperatures and/or heat loads. Conversely, a relatively high thermal resistance heat sink minimizes TEM power for sufficiently low ambient temperatures and heat loads. In the problem considered, total footprint of thermoelectric material in a TEM, thermoelectric material properties, component operating temperature, relevant component-side thermal resistances, and ambient temperature range are prescribed. Moreover, the minimum and maximum rates of heat dissipation by the component are zero and a prescribed value, respectively. Provided is an algorithm to compute the combination of the height of the pellets in a TEM and the thermal resistance of the heat sink attached to it, which minimizes the maximum sum of the component and TEM powers for permissible operating conditions. It is further shown that the maximum value of this sum asymptotically decreases as the total footprint of thermoelectric material in a TEM increases. Implementation of the algorithm maximizes the fraction of the power budget in an optoelectronics circuit pack available for other uses. Use of the algorithm is demonstrated through an example for a typical set of conditions.