A power plant operates with a heat source reservoir at 350oC and a heat sink reservoir at 30oC. It has a thermal efficiency of 55% of the Carnot engine thermal efficiency for the same temperature levels. What is the thermal efficiency of the plant?
Temperature of source, T1 = 350oC = 350 + 273 = 623 K
Temperature of sink, T2 = 30oC = 30 + 273 = 303 K
h Carnot = 100 x (1 - T2/T1) = 100 x (1 - 303/623) = 48.64%
Thermal efficiency of the plant= 55% of the Carnot engine efficiency (given)
= 0.55 x 48.64 = 26.75%