First, it seems that the engines might be practical—we will get to what that means in a bit—even though they use the same set of thermal operations as a Carnot engine. Cyclic heat engines seem ...

The efficiency also tends to decrease, because it requires large temperature differences as given by the famous Carnot heat-engine equations. For these reasons, liquid- or gas-driven heat engines ...

And the conversion efficiency is ``how much heat added to the Carnot cycle is converted to rotational energy'', so it can be obtained by E / (Q H). As long as Q C exists, E will never be 1, i.e. 100%.

The black dotted line shows the generalized Carnot limit for an engine interacting with a hot squeezed thermal bath. The results shown are performed at a temperature ratio of 0.88. Arxiv – Nanoscale ...

Such a nano-heat engine could be far more efficient than, ... E. Lutz. Nanoscale Heat Engine Beyond the Carnot Limit. Physical Review Letters, 2014; 112 (3) DOI: 10.1103/PhysRevLett.112.030602; ...

Such heat engines typically operate at 30-40 percent efficiency, such that ~ 15 TW of heat is lost to the environment To be competitive compared to current engines and refrigerators (efficiency 30-40 ...

A physicist solves an old thermodynamic puzzle and demonstrates directly from the second law that entropy disappears at absolute zero.

Engineers have reported on the development of a microscopic motor operating between two thermal baths, that is, a micro Carnot engine. In a recent study published in Nature Physics, ICFO ...

More information: J. Roßnagel, et al. "Nanoscale Heat Engine Beyond the Carnot Limit." Physical Review Letters. DOI: 10.1103/PhysRevLett.112.030602. Also available at arXiv:1308.5935 [quant-ph] ...

Stirling engines, named after the Scottish inventor who created them in 1816, offer the highest theoretical efficiency of any heat engine—the same as the Carnot efficiency.