Via CarbonSignal blog comes the following post and Sankey diagram:

“Tri-generation, also known as combined cooling, heat and power (CCHP), is a combination of co-generation, known as combined heat and power (CHP) with an adsorption or absorption chiller to provide water chilling. More information of co-generation can be found here. The chilled water can then be used in refrigeration or air conditioning systems. The engine is connected to a generator which can supply electricity to the site or export electricity to the grid. Typically about 38% of the energy supplied as fuel to the engine is converted to electrical energy.

The rest of the energy leaves the engine as heat via the hot exhaust gases, the coolant system and the oil system. A large amount of the waste heat can be recovered through heat exchangers and can be used to supply all hot water to heat domestic hot water, supply heat to a HVAC system, or supply a chiller to provide all chilled water.

Alternatively the system can be designed to supply a mix of both hot and chilled water to match the site loads. The use of a heat recovery system and chiller can increase the efficiency to between 67- 85% depending on the mix of chilled and hot water required.”

Architect Ziya Buluch has a comprehensive description of his project ‘The Nest’ on his blog. The Nest is a green building which is planned to have no external primary head demand.

Scroll down to the end to find this Sankey diagram:

The flows represent the heat energy. Overall demand for heat 37.46 kWh per square meter per year. 12.08 kWh/m2a is from solar panels, 25.38 kWh/m2a from an air-source heat pump (whaterver that is…).

Untypical Sankey diagram, but nevertheless interesting. Flows are not really to scale (compare the 12 kWh inflow and the 6 kWh losses outflow, which should have half the width, or to the 25 kWh inflow that should be roughly twice as wide). Unicolor grey flows with a slight gradient from left to right.

I had to stop posting for a few days because I had trouble with page hijacking. Set up WP anew with the help of a friend (thanks Chris!). To get going again after this break, here’s a misc Sankey diagram from my collection:

The upper part depicts a process diagram of a gas-powered steam boiler system. Below are the energy flows as a Sankey diagram. Values are in percent, showing the yield. Out of the input energy (100%) we have 31.5% of the energy in low presseure steam and 42% in electric energy. Don’t know where I picked this duiagram from, will have to check if I find the source of this.

Managed to translate most from a website on process heat from solar systems installed in a brewery I had found recently. (again a Sankey diagram from a brewery!). The article sports four different Sankey diagrams for the energy flows in the brewery: one for the entire calendar year 2010, and three further ones for January (winter mode), March (transition period) and July (summer mode) of the same year. This work at Hofmühlbrauerei Eichstätt brewery was apparently supported by Technical University of Chemnitz.



Energy is obtained from three different solar collector fields with different harvest. Flows are in kWh. Energy harvest in March was 75.158 kWh, and in July went up to 132.155 kWh. A description of the whole system and photos can be seen on this page (text in German only).

There are three consumers (the three pink boxes at the right)) that each have different demands depending on the season: Indoor heating (“Raumheizung”), brewing water and domestic water pre-heating (“Brau- und Brauchwasservorwärmung” – Google Translate didn’t help me on this one…) and warm water for the bottle washing machine (“Flaschenwaschmaschine”).

While in winter most of the energy from the solar collector system is directed to indoor heating, in summer it is the opposite: since no indoor heating is needed the whole energy harvest can go to water heating for the other machines. The storage tanks also have a color scheme indicating the temperature.

Very nice! Good work!

The below two Sankey diagrams can be found in the following open access article: A. Kavga, G. Alexopoulos, V. Bontozoglou, S. Pantelakis, and Th. Panidis, “Experimental Investigation of the Energy Needs for a Conventionally and an Infrared-Heated Greenhouse,” Advances in Mechanical Engineering, vol. 2012, Article ID 789515, 16 pages, 2012. doi:10.1155/2012/789515

Conventional forced air heating of a greenhouse

Infrared (IR) heating of a greenhouse


The arrows have a fancy 3D effect. No quanitative reference is given, but the article mentions that “the diagrams are qualitatively representative of the energy flow of systems utilizing burners”.

At the Technical University of Munich a project on Engine Combined Cycle (ECC) Power Plants aims at “improving the electrical efficiency of an engine combined cycle plant by using the exhaust gas heat in a steam cycle”.

The following Sankey diagram is shown to illustrate where heat can be recovered.

No absolute values are given, but the Sankey arrows represent the percentage of the primary energy. Four percent of the energy in the steam process can be recovered to add a total of 47.8% efficiency output of electrical power to grid. Losses branch out to the right side and are primarily via the cooling water and condensate at the steam process. The whole Sankey diagram is presented in a simple single-color design.

This website on energy optimized building features a case study of a students dorm building at Wuppertal, Germany. [On a side note: it is quite striking that when I browse for new Sankey diagrams on the web, I come across them on German websites. Herr Sankey could well have been a German…]

The two Sankey diagrams shown along with the article visualize the heat energy flows before and after the optimization measures taken.



Flows are in kWh per square metre per year. The first diagram breaks down heat consumption into heat used for room heating and for warm water preparation. In the second a new heating system has been installed providing heat mostly over the air circulation system. Only some static radiators remain. [Thanks Thomas for helping me with the translation/explanation].

Apart from the use of a fancy color, the Sankey diagrams are well done and comprehensible. Flows are to scale.

The PDF product brochure of Thermax Multi Energy Vapor Absorption Machines (Source: Thermax India Ltd, Pune) features a Sankey diagram comparing a conventional system (green) with a system that has heat recovery (blue).

The Sankey diagrams are labeled as “indicative only”. Fair enough, since the small flows (e.g. “radiator loss” and “alternator loss”) are not to scale. In fact this over-emphasis of the smaller flows seems to lead to an underrepresentation of the actual benefit of the Thermax system: The 80% “net useful output” of the blue diagram is only shown with a width of roughly 50% [measured with a conventional ruler off my screen…]

Any other product brochures with Sankey diagrams you are aware of? I actually found this pictured in a scientific paper (DOC).

It is also a rare example of a top-down orientation in a Sankey diagram. Most of the ones you find are left-to-right or bottom-to-top oriented.