Fairly sure co-generation in commercial power plants uses the turbines exhaust heat to boil water for a steam trubine. Could be other steps in a fashion similar to the old triple and quadruple expansion steam engines or prior centuries. These used the exahust from the first piston to drive a larger lower pressure second, third, and even 4th pistons, further extracting energy out of the steam pressure until it had dropped to practically nothing, more than hot water under 212 degrees, which could then be used for other purposes, like hot showers.
http://www.bing.com/images/search?q=...EBAE49&first=1
regards
Mech