1. The problem statement, all variables and given/known data A hot gas stream at 600K and 200 kPa is cooled at constant pressure to 300K in a pipe by direct thermal contact with the atmosphere. The mass flow rate of the stream is 0,1 kg/s and the atmospheric temperature and pressure are 300K and 100 kPa. Modeling the gas as an ideal gas with constant specific heat determine; a)heat transfer rate to the atmosphere b)entropy generation rate associated with the cooling process c)if the hot gas stream is used to produce mechanical power by operating a heat engine between the stream and the atmosphere determine the maximum shaft power produced d)demonstrate that the mechanical power produced in part c is proportional to the rate of entropy generation in part b 2. Relevant equations 3. The attempt at a solution Since we don't know what the gas is, i write down c representing Cp (constant pressure problem) dT = T2 - T1 (change in temp) dS = S2- S1 (change in entropy) a) Q=mcdt = 0,1c.(600K-300K) = 30c (heat transfer rate to the atmosphere) b) dS = Sgen + (Q/T) so Sgen = dS - (Q/T) dS = mcln(T2/T1) = 0,1cln(600/300) = 0.07c Sgen = 0.07c - (-30c/300K) = 0.17c (entropy generation) What did i miss? I am confused because i didn't make use of pressure throughout my calculations. c) max efficiency n = 1 - (Tcold/Thot) = 1 - (300/600) = 0.5 Q.n=Work 30c.0,5=15c (maximum shaft work) d) i couldn't come up with something on this.