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 diagam is presented in a simple single-color design.

The report describes that “Sankey diagrams enable visual representation of both quantitative and qualitative characteristics of water entering and leaving different activities and therefore serve as a good communication aid.”

The above diagram does not show any unit, but presumably is meant to be in cubic metres (per year?). It shows water (blue) and waste water (grey) flows, as well as evaporation losses (red).

More water Sankey diagrams of similar style can be found on pages 19 through 23 in this workshop presentation on ‘The Importance of and Difficulties in Water Accounting’.

Same topic as in my previous post, heat flows and losses, this time in a continous furnace. Recovered heat loop is strange: arrows gets wider in the curves, as if painted by hand. Funny serpent arrow for opening (radiation) losses. No values given. All arrows have the same colour. Source: Article ‘Quest for Fire – Combustion Basics’ by by Daniel H. Herring. Published October 2, 2009 on Industrial Heating. The International Journal of Thermal Technology.

Notes: Boiler Efficiency Sankey Diagram. Uncommon arrow head colouring. Percentage breakdown. Source: Energy Efficiency Analysis and Practices Blog. This Sankey is apparently produced by a software on boiler efficiency (BIOEFF v1.07), further analysis needed.

In fact, as can be seen from the Sankey diagram shown in the paper, the majority of electrical energy consumed in a data center is for cooling, UPS and other supporting infrastructure equipment.

No typical DCIE is given, but the samples shown suggest that it ranges between 30 and 50 %. Several constraints have an impact on the actual DCIE, such as the IT load itself and the outside temperature, and thus should be reported along with the measurement.

A nice idea to present the breakdown on electricity consumption as a Sankey diagram, rather than as a (boring?) pie chart, especially when speaking of “power flows”.

Download the WP #154 from APC’s website.

Here is a Sankey diagram that shows the recovery of energy from exhaust gas.

Download a description of the TES here (PDF, 291 KB) or view a high resolution version of the above Sankey diagram from their press picture gallery.

The Sankey arrows representing the losses bend down sharply, they remind me of the Iguazu Falls. Neat 3D images of the equipment are placed on the diagram to visualize the process steps where energy is lost. The whole thing hovers over the ground throwing a faint shade. The graphic designer who did this really merits an applause.

If ever I launch a ‘Best Sankey Diagram Award”, this one will have good chances to win it. Any sponsors out there? Any volunteers for the award jury?

I have “translated” the given values into a Sankey diagram, using the original image as a background layer. This works quite fine, apart from the very thin (1%) flow of friction losses.
On a side note: this is the first time I am presenting a right-to-left oriented Sankey diagram on this blog.

The author concludes, that energy can be saved on the engine and transmission, however the mode of operation (e.g. to reduce the effect of wave resistance), and hull maintenance. Read more interesting details.

One success story dates back to 1997, and describes how an energy efficiency study of fired heaters (i.e. boilers) was carried out in a Nafta producing facility in the Veracruz state of Mexico. As a result of the study, several suggestions for optimization were implemented. Fuel consumption could be reduced by 23-24 %, while the efficiency of the ovens could be raised by 13% (calentador BA-2001 B) and 16% respectively (calentador BA-2001 A).

Para los hispanoparlantes: el título oficial del proyecto fue “estudio técnico económico e ingeniería conceptual realizada a los calentadores a fuego directo BA-2001 A/B de la planta hidrodesulfuradora de naftas, del C.P.Q. “La Cangrejera”, ubicado en Coatzacoalcos, Veracruz” (otro candidato para el concurso Mundial de titulos largos).

The heat losses are shown as Sankey diagrams. The first describes the optimal situation, with an energy efficiency of 82,4 % “as guaranteed” by the maker of the fired heater.

The two other Sankey diagrams show the energy balance of the heaters A and B before the implementation of the measures. They run with an efficiency of 60,6 % and 62,35 %.

The arrows branching off at the top show the heat losses. I like the fancy icons that show how energy is lost through the walls, because of deteriorated or insufficient insulation, and heat energy in the effluent gases. The flows are given in MMBTU/h (millions of BTU per hour).

Unfortunately two of the diagrams are not to scale: The arrow to the right in the second diagram should be roughly 2/3 of the width on the left side. It is about 4/5 (or 80 %) of the width, similar to the width in the first Sankey diagram. This is a visual exaggeration of the inefficiency. However, I refrained from featuring this in my informal “Lying with Sankey diagrams” series.

It is a comparison of how much energy is being used to power a lamp. The Sankey diagrams does not work with absolute values, but rather are scaled to one unit of “useful light”. You should read them “upstream” (from right to left) for better understanding. The first two diagrams (a and b) are regular incandescent bulbs. The third one (c) is a compact fluorescent light (CFL) bulb.

The bulb in the first scenario (a) is powered with energy from a coal/gas plant, which has an efficiency of only 35%. Further losses occur during transmission and distribution and at the bulb itself (98%).

In the second diagram (b) a combined cycle gas turbine (CCGT) power station provides the energy. It has a 50% efficiency.

The third one (c) uses energy from a common coal/gas plant again, but the customer uses a CFL bulb.

“A CFL is about 5 times more efficient so the losses reduce from 98% to 90%. In other words, a 20 W CFL produces about the same light as a 100 W incandescent bulb. Translated through the supply chain this means that the primary energy use is reduced to 64 units per unit of light, even if [a coal/gas plant] is still used. This is an 80% reduction in energy use. The benefit of a demand-side technology addressing the most inefficient part of the supply-chain is clear.”

Thus, the same amount of useful light can be produced at 64 units of energy in contrast to 320 units of energy.

Note: In the original publication the Sankey diagrams are not to scale to each other, so that the arrows for the primary energy values (320 units in the first, 224 units in the second, and 64 units in the third one) on the left all show the same magnitude. By bringing all three flow diagrams to the same scale, the significant difference between them becomes even more visible.

The Sankey diagram shown in this post on the Green Car Congress blog visualizes that only 25% (green arrow) of the energy from combustion is used as “effective power” for mobility and accessories, while 40% of the energy is lost in exhaust gas.

Projects are being carried out at John Deere, Caterpillar, Detroit Diesel and Mack Trucks, to name just a few.

“Seven of the twelve projects focus on advanced combustion technology with a heavy focus on HCCI (Homogeneous Charge Compression Ignition). There is also an diesel-compressed-air hybrid truck powertrain under development. The remaining projects deal with technologies to convert waste heat from engines to electrical or mechanical energy.”

The inefficient energy use of car engines and other vehicles are the main reason for the transport sector being (next to energy generation and transmission) the sector where most energy is being lost (see this post).

“…over half of the energy produced for our domestic market goes to waste. Fully two thirds of the energy produced by electrical generation and distribution goes to waste.”

This Sankey diagram shows the energy carriers on the left side, the sectors where energy is consumed (noteworthy: traffic has a larger share than industry) as midpoint groups, and a breakdown to useful and lost energy on the right.