In this study, the thermoelectric performance of an integrated thermoelectric device (iTED) with rectangular, round end slots, and circular flow channel designs applied to waste heat recovery for several hot stream flow rates has been investigated using numerical methods. An iTED is constructed with p- and n-type semiconductor materials bonded to the surfaces of an interconnector with flow channels drilled through it. This interconnector acts as an internal heat exchanger directing waste heat from the hot stream to thermoelectric elements. The quantity of heat extracted from the waste heat source and the subsequent amount of electrical power generated P0 from the iTED is increased significantly for the circular flow channels, followed by round end slots and rectangular flow channels, respectively. At Re = 100, the round end slots and the circular flow channels showed nearly 2.6 and 2.9 times increment in P0, and 1.5 and 1.65 times in when compared to the rectangular flow channels values. Conversely, when Re is increased from 100 to 500, the iTED with rectangular flow channels showed 2.67- and 1.6-fold improvement in P0 and , respectively. However, the circular configurations showed 2.27- and 1.41-fold increases in P0 and values, respectively. Within theRe range studied, the inclusion of flow channels’ pumping power in calculations showed negligible effect. For an iTED with circular flow channels, an increase in a cold side convective heat transfer coefficienthc resulted in an enhancement inP0 and values. Besides a hc effect, the heat loss to the ambient via convective and radiation heat transfer exhibited an increase inP0 and decrease in .