Month: October 2020

Sankeys with circular links

Guus, a reader of this blog, DMed me to ask whether I “knew of any (open source) JavaScript libraries that can generate circular Sankey diagrams”?

Many of the Sankey diagrams I see on the web are created using d3.js by Mike Bostock. Typically these diagrams are left-to right oriented and have a column structure. What is less common are feedback loops or circular Sankey arrows, like the pink ones in the figure below.

The place to look for is Tom Shanley’s Block.

Here you can find many samples for:

Guus, I hope you can find what you are after there. Enjoy!

Sankey Diagram for Air Compressor

A comment from a reader pointed me to this Sankey diagram for energy flows in an air compressor system. It can be found as a sample on the web page of VHK Research Engineers. VHK uses Sankey diagrams to “get the message across”.

(Image copyright: European Union, author: VHK)

This is a rare example of a top-down oriented Sankey diagram. There are no absolute numbers, rather we see the 100% energy being turned into useful work, and off-heat, which could potentially be recovered.

Nice piece of art, and I invite Rene to comment on this…

Energy Consumption Logistics Center

Here is another Sankey diagram out of Germany. Found this in a 2017 doctoral thesis titled ‘Wechselwirkungen und Auswirkungen von Planungsalternativen auf die Gesamtenergiebilanz und die CO2-Emissionen von Logistikzentren’ by Julia Freis, Lehrstuhl für Fördertechnik Materialfluss Logistik, Technical University Munich (TUM).

From what I understand using Google Translate this seems to be one of the energy scenarios (maintaining a 17°C temperature) for a logistics hub. Flows are in kWh per year.

China Carbon Emissions from Energy

Energy generation in China is dominated by the use of hard coal. This Sankey diagram is from an article titled ‘A Method for Analyzing Energy-Related Carbon Emissions and the Structural Changes: A Case Study of China from 2005 to 2015’ by Honghua Yang, Linwei Ma and Zheng Li (Tsinghua University) in: Energies 2020, 13, 2076; doi:10.3390/en13082076. It shows carbon flow and emissions (I take that as CO2 only, although it might include CH4 if biogas was used)

Published under the terms and conditions of the Creative Commons Attribution(CC BY 4.0) license

Depicted are energy-related carbon flows in China in 2015. Unit of flow is 10 Mt C, which in the last column also translates into Mt CO2.

The sectors Transport (“Vehicle”), Industry (“Factory”) and Buildings are further broken down into the individual services the energy provides, like illumination, thermal comfort, hygiene.

There is another energy flow diagram for China in 2015 in this article, and it shows that there are also other energy sources (hydro, wind, nuclear, solar), but these don’t show up in the carbon flow diagram.