Temperature stabilization is important in many microelectronic devices due to thermal constraints on device operation and lifetime. The work described here is an investigation of thermoelectric phenomena in bipolar devices, specifically the p-n diode. Current injection can modify the Peltier coefficient at interfaces; this can give rise to thermoelectric cooling or heating depending on device parameters. The bias-dependent Peltier coefficient is modeled using self-consistent drift-diffusion, and implications for device design are examined. The different regimes of bias for which cooling is achieved are described, as well as the effects of device length, doping, and heterojunction band offset. Extensions of the model are given for applications such as the internal cooling of semiconductor laser diodes.