− θ − θ = θ − θ θ − θ − − = − − − = − = = + = − = + = = α α Pulley Thermometer Pulley 1 Q2-1 (out) P W Z 2 Water W1-2 (In) Adiabatic vessel V Paddle Σ = Σ δ δ δ δ ∫ δ − δ Heat source TH QH Heat source Engine E W = QH – Q2 Q Q2 Engine E W Heat sink T2 Q=W An Impossible Engine A Possible Engine High temperature sink Heat W=0 Pump or Refrigerator System boundary Low temperature source Impossible = − γ − − = − = − − = = − η = − − η = η =− + =− =− = + Hot reservoir T-1 1 Ref or H.P. Q1 1 4 4 W P T 3 2 2 Cold reservoir T-2 Q1 3 V Q2 S = − = − Hot reservoir T1 100kJ 100 kJ 80 kJ Irreversible energy =15% assumed Reversible engine =60% Reversible engine (assumed) 40 kJ H =60 KJ 40 kJ 20 kJ Irreversible energy w = 15 kJ 25 kJ Cold reservoir T2 Cold reservior = = = ∫= 2 T2 T 1 0 T1 S1 S S2 = × − = δ δ ∫ ≤ ∫ = ∫ < ∫ > = = = = − − = = = = − η = = + − − − = + = = = = ∫ = ∫ = ∫ > ∴ = ∫ ∫ ∫ + ∫ = − = ∫ = − = ∴ ∫ = − = ∴ =