TITLE.PM5

238 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-1.pm5 Source Sink HE Q = 1500 kJ/min 1 W = 8.2 kW Q 2 HE = Heat engine Solutio ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 239 dharm /M-therm/th5-1.pm5 T = 308 K Ambient air 1 T = 261 K Freezer 2 HE Q 1 Q 2 W Q ...

240 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-1.pm5 Solution. (i) Heat requirement of the house, Q 1 (or heat rejected) = 2 ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 241 dharm /M-therm/th5-1.pm5 (ii)The net work transfer, W = ηcarnot × Q 1 Q ηcarnot W Q ...

242 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-1.pm5 Example 5.10. A fish freezing plant requires 40 tons of refrigeration. T ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 243 dharm /M-therm/th5-2.pm5 +Example 5.12. A reversible heat engine operates between t ...

244 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-2.pm5 Since, W 1 – W 2 = W = 400 kJ W 2 = W 1 – W = 1670 – 400 = 1270 kJ ∴ Q 4 ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 245 dharm /M-therm/th5-2.pm5 Heat removal rate from the refrigerator, Q 1 = 1440 kJ/min ...

246 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-2.pm5 coupled to a Carnot engine which absorbs heat from a source which is mai ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 247 dharm /M-therm/th5-2.pm5 Example 5.15. Two Carnot engines work in series between th ...

248 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-2.pm5 T (300 K) 2 T (600 K) 1 Carnot refrig. Carnot engine T 3 Q 1 ′′ Q 1 ′ Wc ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 249 dharm /M-therm/th5-2.pm5 (ii) Efficiency of Carnot engine, ηcarnot engine = TT T 13 ...

250 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-2.pm5 ∴ Q Q 1 4 = T T TT TT 1 4 43 12 − − F HG I KJ = − − F HG I KJ 1350 350 3 ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 251 dharm /M-therm/th5-2.pm5 Solution. Boiler temperature, T 1 = 160 + 273 = 433 K Cond ...

252 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-3.pm5 Heat transferred in the boiler per kg of fluid, Q 1 = h 2 – h 1 = 2760 – ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 253 dharm /M-therm/th5-3.pm5 Hence when the system passes through the cycle 1-L-2-M-1, ...

254 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-3.pm5 Hence equation (5.18) may be written as dS = δQ T R F HG I KJ ...(5.19) ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 255 dharm /M-therm/th5-3.pm5 Since entropy is a thermodynamic property, we can write dS ...

256 ENGINEERING THERMODYNAMICS dharm /M-therm/th5-3.pm5 By including any system and its surrounding within a single boundary, as ...

SECOND LAW OF THERMODYNAMICS AND ENTROPY 257 dharm /M-therm/th5-3.pm5 The entropy attains its maximum value when the system reac ...