Optimal Pellet Geometries for Thermoelectric Refrigeration

For a thermoelectric module (TEM) operating in refrigeration mode, the cooling flux provided by it, its coefficient of performance and its operating voltage per unit footprint are key parameters. They are provided here as a function of the temperatures on both sides of a TEM, current flow through it, electrical contact resistance at its interconnects and the geometry, material properties and packing density of its pellets. The pellet heights which maximize TEM performance (i.e., cooling flux they can accommodate for a specified temperature difference) or efficiency (i.e., coefficient of performance) at a specified performance are derived. Moreover, it is shown how to tune the operating current and voltage of a TEM by adjusting the cross-sectional area of its pellets. The analysis is performed in both the absence and presence of electrical contact resistance at the interconnects in a TEM. Implications of the results are placed in context for representative conditions.