Thermal Efficiencies Using the
Kelvin Temperature Scale

•Thermal efficiency = 1
– TC/TH

•Example
Problem: What is the maximum thermal efficiency of a steam engine
that uses steam at 150oC and exhausts it at 95oC?
•Solution: TE = 1 – TC/TH

•So, 1 – 273 + 95/273 +
150 = 368/423=

•1 – .87 = .13 = 13%