We describe the fabrication of thermoelectric modules based on Half-Heusler TiNiSn and FeNbSb and their performance assessment under different boundary conditions. Module design is guided by a multiphysics model implementing experimentally determined thermoelectric materials properties. We consider two types of boundary conditions: first, imposing fixed cold- and hot-side temperatures onto the module, and second, imposing fixed values for the heat transfer coefficients between module and heat sink and source, representative for a waste-heat-recovery system using the exhaust heat of an internal combustion engine. We compare the modeling results with experimental data obtained from Half-Heusler modules integrated into a heat exchanger mounted to the exhaust of a compact van. [ABSTRACT FROM AUTHOR]