A system and method of detecting recirculation within a rack server system. A heat transfer model is constructed for a rack server system. A recirculation zone is specified, and hypothetical recirculation temperatures are input at the recirculation zone. The heat transfer model predicts temperatures elsewhere in the rack severe system, and a predicted temperature profile is computed. Actual temperatures in the rack server system are sensed, and an actual temperature profile is also generated. The actual temperature profile is compared with the predicted temperature profile to detect potential recirculation.