This study provides the influence of different heat exchanger internals (helical pipe coils, heating plugs, pipe registers) and reactor bottom shapes (torispherical/dished (Kloepper-shape), hemispherical, and flat) on the flow field, the turbulent kinetic energy, and the ratio of tangential flow in stirred vessels, based on extensive stereo PIV measurement series in refractive index-matched, optically completely accessible systems. The investigations impressively show advantages and disadvantages of the various equipment, which have a massive influence on both heat transport and the flow.