Thermoelectric devices are complicated in that they are always part of a larger thermal system. This system, along with the specific heat loads, heat exchangers, and ambient conditions, all play a role in the effectiveness and design of the thermoelectric device. However, one can say that a thermoelectric cooler allows for sub-ambient heat pumping, meaning it can disrupt the typical “straight line” gradient of heat flow in a system from hot to cold in a conventional thermal circuit. Heat flows downhill, so to speak. The insertion of a thermoelectric cooler, or TEC, between the component and reject heat exchanger can allow for a temperature inversion where the component can be kept cooler or temperature-controlled without a straight-line dependence on ambient conditions.