Month: November 2013

Energy Embedded in Water

David Wogan at the Scientific American blogs that “Over 12 percent of all U.S. energy consumption is directly related to water”. This was identified in a 2012 study by researchers of UT Austin.

The values in this Sankey diagram are for 2010 in trillion BTU. Energy is used for direct and indirect water services such as steam generation.

The author argues “The study also identifies an interesting policy issue: roughly 25% more energy is used to heat, cool, or pump water than is used for lighting (in the residential and commercial sectors) in the United States – about 5 quads. So why are more efficiency policies and technologies targeted towards lighting and not water conservation?”

Retrofit for a Maritime Vessel Engine

From what seems to be a 1998 abstract on retrofitting the main engine of the Japanese vessel Fukaemaru come these two Sankey diagrams. Found this on the website of the Kobe University Martime Faculty. Both nice plain black&white.

The first one shows energy efficiency of the original gas turbine equipped machine room. The base seems to be 100% energy (the label actually says ‘fuel exergy’) and the useful energy (arrow going straight up, labeled 出力) is 15.48% only. Losses branch out as arrows to the left and to the right.

The other Sankey diagram shows the energy flows for a diesel powered main engine. Efficiency is up to 37.38%

Read the full abstract here (in Japanese).

On a side note: funny to see that in the description of the figure at the bottom the author actually turned “Sankey Diagram” into a “Keysan Diagram”…

Energy Sankey for UCL Campus

The company with the catchy name ‘Useful Simple Projects‘ is “a design led consultancy [that works] with organisations and on major urban development projects to develop sustainability strategies, and identify opportunities for innovation”.

Here is a Sankey diagram they did for an energy strategy study for University College London’s Bloomsbury Campus.

Values are probably for a year. The Sankey diagram shows energy consumption in GW (red and blue arrows). The UCL campus has a cogeneration plant, so heat (green arrow) can be produced and distributed by district heating grid.

The numbers in grey show the carbon emissions in tons of CO2 linked to the energy consumption (most likely using characterization factors for electric energy production in the UK and for provision of natural gas). UCL has a low carbon strategy for the next years and this study helps them to review their goals.

This Sankey diagram is … simple and useful.