GC: n

CT: Combined Cycles in Stationary Gas Turbine for Power Production. The turbine entry temperature in a gas turbine (Brayton) cycle is considerably higher than the peak steam temperature. Depending on the compression ratio of the gas turbine, the turbine exhaust temperature may be high enough to permit efficient generation of steam using the “waste heat” from the gas turbine. A configuration such as this is known as a gas turbine-steam combined cycle power plant. The cycle is illustrated in Figure 8.18.
The heat input to the combined cycle is the same as that for the gas turbine, but the work output is larger (by the work of the Rankine cycle steam turbine). A schematic of the overall heat engine, which can be thought of as composed of an upper and a lower heat engine in series, is given in Figure 8.19. The upper engine is the gas turbine (Brayton cycle) which expels heat to the lower engine, the steam turbine (Rankine cycle).

S: http://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node67.html (last access: 24 February 2015)

N: 1. combined (adj): From combine (v.), early 15c., from Middle French combiner (14c.), from Late Latin combinare “to unite, yoke together,” from Latin com- “together” (see com-) + bini “two by two,” adverb from bi- “twice” (see binary). Related: Combinative; combined; combining.
cycle (n): late 14c., from Late Latin cyclus, from Greek kyklos “circle, wheel, any circular body, circular motion, cycle of events,” from PIE kw(e)-kwl-o-, suffixed, reduplicated form of root kwel-, also kwele-, “to roll, to move around, wheel”.
2. In electrical power generation, a system in which a gas turbine drives a generator to produce electricity, and the hot exhaust … from the gas turbine is used to produce steam in a boiler, which is used to drive a steam turbine to drive a generator (conventional cycle) to produce electricity … Thus, electricity is produced by a gas turbine and a steam turbine. A combined cycle might consist of a conventional cycle plus a topping cycle or bottoming cycle or both.

S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=combine&searchmode=none; http://www.etymonline.com/index.php?allowed_in_frame=0&search=cycle&searchmode=none (last access: 24 February 2015). 2. TERMIUMPLUS.

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CR: electrical energy, energy, heat energy, Rankine cycle, thermal power plant.