Originally Posted by jt20

Here we go.

As the HOT exhaust leaves the high pressure area and enters low pressure - it is given the space it needs to release potential energy. By expanding it cools down. It is the place whrere this expansion ocurrs that allows a turbo to harness the otherwise wasted engergy (heat energy) in exhaust.

by expanding the gasses across impellers of different ratios and vector fields (quote FI here), the basic fans (impellers) capitalize on TWO DIFFERENT VOLUMES of A gas body at different temperatures as it (gas body) changes across them (simple fans)

turbos need heat (or an available means of pressure differential)
turbos need simple fans