Question

SP35: A power cycle operates between a high temperature reservoir at temperature Th and a cold temperature reservoir at temperature Tc. Determine whether the cycles below are reversible, irreversible, or impossible. For this problem you do not need to follow completely the class homework solution format, but draw a system diagram and write down the needed basic equations. = cycle (a) Th = 600°C, TC =-5°C, QH = 1200 kJ, W = 850 kJ (b) TH = 1000°C, Tc = 30°C, n = 0.7619 (c) TH = 200°C, TC =-20°C, Qc = 1000 kJ, W., = 800 kJ (d) TH = 700°C, Tc = 200°C, QH = 1200 kJ, Qc = 480 kJ cycle

Partial answers I have are: a) impossible b) reversible. Please use the partial answers to verify yours and show all steps in working so I can learn as well. Thanks!

Answer 1

and a 1 A power cycle operoding between high temperature reservoir cold temperature Peyovor (T) for different case we have to find out posibility operation and identify that is it is possible then it is reversible 06 IoToVox sibe. As we know, Cornot is the most efficient cycle, Kode bessible between two givor temperature (Thamd TC) So any cycle having efficiency groter E than cars not gole for given temperatures is impossible. Otherwiso possible 30, We can say , foo Tycod Tc (given) if 0 h > cromat ; impossible Tec Want ii) n <ncarnet ; Possible fig: Block diagrama Rours Ergile A practieke ! A practical Cyde A practical gde have efficere less than Carnot be caubo og irreversibility the So, if n ncaonot Jevsible yolc and if na ncoronot L. darovercle Cycle Now, 9) The Goo'c = 873K 5 Ts= -5°C = 268 K OH = 1200 kJ ; Woyce 250 kJ So, 0.69 'carnot To TH and h Weyde 850 POD 0.70 - OH for ca); this '' n > n carnet ; 20, y de is impossible 303 K b) Given; TH= 10000 = 1273K ; T = 30°C n=0.7619 Tc 90 =) - carrot . Here, = 0.7619 Ти na ne bo, this cycle is possible and reversible too. c) Given; Th= 200 C = 473 K ; Te = -20°c = 253k Oc = 1000 KJ ; Wade 800 KJ 30, comot 1- TC 0.4651 TH and OH = 1000-4800 -1800 KJ OctWayde Wcycle OH 80 n = 800 1800 0.4444 Here nancarrot ; 80 this cycle is possible but irreversible. d) Given; TH= 700°C = 973k ; T = 200°C. =4738 OH = 1200 KJ i Oc= 480 KJ = 1 - Tc so, comot = 0.5138 TH and Weyde OH-Oc = 1200-480 = 720KT . 0-6 Here, ha le do this gole is impossible CS Scanned with CamScanner 80, Waycle 720 1200