This work investigates the feasibility of using LVGs (longitudinal vortex generators) to improve heat transfer in TEG (thermoelectric generator) systems. A coupled fluid-thermal-electric model is established with COMSOL Multiphysics (R) to study the effects of LVG height, LVG attack angle, and hot-side inlet gas temperature. We find that LVGs can significantly enhance the heat transfer performance, power output, and thermal conversion efficiency due to the generated longitudinal vortices, especially at small LVG attack angles. The performance of the thermoelectric generators with LVGs is best for LVGs that span the full height of the channel at the highest temperature examined (550 K), where the heat input, net power and thermal conversion efficiency are enhanced by 29%-38%, 90%-104% and 31%-36%, respectively, compared to smooth flow channel. As the hot-side inlet gas temperature decreases, the pumping power remains constant and requires a larger portion of the power output since the heat input and power output are significantly reduced. Therefore, it is not beneficial to use tall LVGs at lower hot-side inlet temperatures and higher inlet Reynolds numbers due to the large ratio of pressure drop to power output, but smaller LVGs are still useful under these conditions. (C) 2015 Elsevier Ltd. All rights reserved.