Question

How would you rank the thermal efficiencies of ideal Diesel, Stirling and Carnot cycles if they operate between the same temperature limits (the same Tmin and Tmax temperatures)?

Answer 1

For given T(max) and T(min) , carnot's cycle is the most efficient one among all other cycle. Carnot's cycle gives the maximum possible thermal efficiency that can be possibly obtained for given temperature limits. It's the benchmark for comparison of cycles.

An ideal sterling cycle is more efficient than an ideal diesel cycle.

For same temperature limits, the area of Pv diagram for sterling cycle is more than that of diesel cycle. This tells us net work done by sterling cycle is more than diesel cycle which makes thermal efficiency of sterling cycle higher than diesel cycle.

So the order is

CARNOT } STERLING } DIESEL for same temperature limits.

Carnot's cycle is the best , while diesel cycle is the least efficient.