Aeronautical Engineering/aeronautics


Sir, can you explain about carnot cycle, is it 100% efficent cycle its possible?

Well Mugesh, you are taking me back 50 years to engineering school. The Carnot cycle is a heat power cycle composed of the following processes:  1) isothermal expansion and reception of heat at temperature T1, 2) isentropic expansion, 3) isothermal compression and rejection of heat at termperature T2, 4) isentropic compression to temperature T1. The complete cycle may be reversed to produce a Carnot heat pump or refrigerator. The Carnot cycle has the highest efficiency of any cycle operating between two temperature limits. It is, however, impractical to use steam as a working fluid in a Carnot cycle.

The Carnot engine efficiency, eta, can be written in terms of the temperature of the heat reservoirs:

eta = (T1-T2)/T1

Therefore, the only way to achieve 100% efficiency would be to have the receiver absolute temperature at 0, which is impossible for a working fluid. So I believe the answer to your question is no. It makes me wonder what would happen in deep space where T2 is almost zero, but even there I believe it is not possible to reach absolute zero in a working fluid.


Aeronautical Engineering

All Answers

Answers by Expert:

Ask Experts


Paul Soderman


Aeronautics, Aerodynamics, Fluid Mechanics, Aeroacoustics, Noise Control, Muffler Design, Wind Tunnel Research.... I know nothing about India - do not ask about schools, jobs, application requirements, career choices, etc. for India. Please, no text message verbiage; I prefer full words in full sentences. Thanks.


38 years as research engineer at NASA


B.S. and M.S. Aeronautical Engineering - U. of Washington, Graduate work Standford U.

Awards and Honors
AIAA Associate Fellow (American Institute of Aeronautics and Astronautics)

©2016 All rights reserved.