Question

Can saturated water vapor at 200 kPa be condensed to a saturated liquid in an isobaric, closed system process while only exchanging heat with an isothermal energy reservoir at 90 C? (Hint: Determine the entropy generation.)

please include given and schematic please

Answer 1

A detailed explanation is given in the image. Hope it's helpful.

SOLED: Given =doo k Pa. = 120.23°C [from steam tables] Saturation pressure of water , Pat Saturation temperature, Isat Temperature of energy reservoir To = 90*C = 363 k As it is Condensation process heat will be released from the System. At 200 kPa, Specific entropy of saturated liquid, St kJ/kg-k Specific entropy of saturated vapour, so = 7.1271 K7/kg-k. = 1.53 Entropy generation is given by =-da + Sgen (5,- -2) + de from soupe T Sgen Too here doy = Enthalpy of evaporation to the reservoir . 2202 :. Sgen = (1.53 - 7-1271) + 3636 Sgen = 0.469 kJ/kg .k So the isobaric Closed System process is possible. > O

RESERVOIR T个 2 8 1 2 12 200 kPa Closed t 2120-23°c System undergoing Maobaric Process = 90°c hevap hevap S s To Here we have considered the closed system to be in an isothermal energy reservoir enclosure, at foc, which exchanges only heat with reservoir