Control volume of hot tank B,
Process = constant volume & mass so no work Energy equation and specific heat
U2 - U1 ≅ mCv(T2 - T1) = 1Q2 = 10 × 0.7448 × 500 = 3724 kJ
P2 = P1T2/T1 = 1.5(P1) = 750 kPa
State: 1 = initial,
2 = final hot
3 = final cold
To fix temperature in cold tank, C.V.: total
For this CV only WHP cross the control surface no heat transfer. The entropy equation for a reversible process becomes