A steam engine boiler is maintained at `250^(@)C` and water is converted into steam. This steam is used to do work and heat is ejected to the surrounding air at temperature 300K. Calculate the maximum efficiency it can have?

Explanation

The steam engine is not a Carnot engine, because all the process involved in the steam engine are not perfectly reversible. But we can calculate the maximum possible efficiency of the steam engine by considering it as a Carnot engine.
`eta=1-(T_(L))/(T_(H))=1-(300K)/(523K)=0.43`
The steam engine can have maximum possible `43%` of efficiency, implying this steam engine can convert `43%` of input heat into useful work and remaining `57%` is ejected as heat. In practice the efficiency is even less than `43%.`