Economic and low-polluting power production has become of vital importance, for this reason the deregulated electricity market has reinforced the quest for cheap, clean, reliable and efficient means of heat and electric power generation. This ongoing trend, which is very likely to continue and even increase in the future, not only includes attempts to improve existing thermal cycles but also to develop new ones, most of which consider alternative fluids and working media.

In the field of cycles based on the use of gas turbines, new solutions have been proposed, such as: the Humid Air Turbine cycle (Rao, 1989, Traverso and Massardo, 2001), the SOFC-GT cycle (Harvey and Richter, 1994a,b, Massardo and Lubelli, 2000) and the Matiant cycle (Mathieu and Nihart, 1998). Moreover, the realization of steam cooling in combined cycles is the main apparent example of innovative design at a cycle level (Stambler, 2000).