Question

. Carnot power cycle operates on 2 lb of air between the limits of 70°F and 500°F. The pressure at the beginning of an isothermal expansion is 400 psia and at the end of an isothermal expansion is 185 psig. Determine the efficiency of the cycle.

Answer 1

$T_2=T_1 = 500 \; °F = 260 \; °C = 533.15 \;K \\ T_3=T_4 = 70 \; °F = 21.11 \; °C = 294.26 \;K$

The efficiency $η = 1 -\frac{T_4}{T_1} = 1 -\frac{294.26}{533.15} = 44.81 \; \%$