Back from a summer break … sorry for neglecting the blog for a couple of weeks. The FIFA Worldcup 2018 prediction from my last post has already become outdated … 😉

Here is a black and white hand drawn Sankey diagram from a doctoral thesis (Giovanni Angrisani:’Experimental and Simulative Analysis of a Micro Trigeneration System based on an Air Handling Unit with Desiccant Wheel’. Doctoral Thesis University of Naples, year unknown).


Instead of color-coded Sankey arrows the different types of energy are shown with different patterns of the arrow head. We can see some typical flaws: width of the arrow changes when going from horizontal to vertical (see ‘Losses 3.24 kW’ arrow branching out to the top), flows not to scale (compare ‘Losses 3.24 kW’ arrow to ‘Losses 6.25 kW’ arrow), overemphasis of some arrows through massive arrow heads.

A retro-style Sankey diagram from the times you would hand-draw such figures.

The summary of a research project under participation of Kempten University of Applied Sciences is presented on a project webpage. It also features this comparison Sankey diagram.

These are in fact two Sankey diagrams “mirrored” at an imaginary horizontal center line. The bottom one facing upwards is the diagram for the baseline representing convential energy systems. The upper one with flows pointing downwards has the same amounts of useful energy (trigeneration 30 % electricity, 47 % heat und 23 % cold), but using 31% less primary energy (see black dashed lines).

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.”