Why are p-type and n-type semiconductor legs connected thermally in parallel in practical thermoelectric devices?

In practical thermoelectric devices, p-type and n-type semiconductor legs are connected thermally in parallel between a common heat source and a heat sink to facilitate efficient energy conversion.1

This configuration is essential because it allows the device to maintain a consistent temperature differential ($\Delta T$) across the semiconductor materials, which is necessary for the Seebeck effect to generate electric power. By arranging the legs in parallel thermally, the device ensures that heat flows effectively from the source through the converter to the sink.12

While the legs are connected thermally in parallel, they are typically connected electrically in series to maximize the output voltage and overall performance of the generator. This structural design, often utilizing multiple pairs of legs, allows for the optimization of thermal conduction and electrical resistance, which are critical factors in the device's efficiency.13