In general, the optimum total thermocouples ratios are always larger than 0.5. That is, the two-stage TEG needs
more thermocouples than the two-stage TEC to obtain high performance. Moreover, the optimum total thermocouples
ratios at maximum cooling capacity are different from those at maximum COP. The optimum total thermocouples ratio
corresponding to the maximum cooling capacity is larger than that corresponding to the maximum COP. This means more
thermocouples in the TEG can lead larger cooling capacity, and more thermocouples in the TEC can lead larger COP.