Question

The efficiency of the Carnot cycle in the clockwise direction, when it acts as a steam or heat engine, 3) is: AWnet E = Aqinput Does this expression depend on the equation of state for the substance being used to run the cycle? Evaluate e for an ideal gas and for a Van der Waal's gas. Do the two equations of state result in the same or different formulas for e?

Answer 1

For an ideal gas: $\epsilon$ = nRT ln(V2/V1)/nRT ln(V2/V1) = 1

For real gas (van der Waal's gas): $\epsilon$ = [nRTln{(V2-nb)/(V1-nb)} + an²{1/V2 - 1/V1}]/{nRTln{(V2-nb)/(V1-nb)} = 1 + an{1/V2 - 1/V1} / RT ln{(V2-nb)/(V1-nb)}