Sankey Diagrams

In 1898, Irish captain Matthew Henry Phineas Riall Sankey wrote an article about efficiency of a steam engine in the Minutes of proceedings of the Institution of Civil Engineers.

He introduced a new type of diagram to represent the fluxes and energy losses in a steam engine, which is compared to an ideal steam engine. The width of the stream is proportional to the amount of heat.

The Thermal Efficiency of Steam-Engines

Diagrams of this type are named after Sankey and are widely used:

More examples of Sankey Diagrams can be found at sankey-diagrams.com blog.

Tools for creating a Sankey Diagram: