CHEN 3101 Lecture Notes - Lecture 1: Sabar, Inta
25 Dec 2014
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Rankine cycle continued: efficiency + enhancements boilier condenser. Along an isobar (1 --> 2) (p = ph) {area under 4 --> 3}/{area under 1 --> 2} = nothing new, but just makes it more precise. Question: how can we increase efficiency: minimize toverbar, c (done isothermally or nearly so, and close to ambient, maximie toverbar, b (how?) Assume t2 = 600 oc, p2 = 1 mpa. Yields output t of 52 oc = t3 =t4. For comparison, carnot cycle: th = 600 oc = 873 k. Rankine cycle: efficiency =~ 32% not all that efficient --> that"s why it"s not good to heat house with electric power liquid. Approach 3) regenerative preheating (use external heat source) Problem :the need to preheat liquid up to tboil (ph) Solution: use steam from turbine to preheat liquid. 2 types: 1) closed preheater - heat exchanger: open preheater - inject steam directily into water pressure must match.
