Tag: building

Green Building Heat Demand Flows

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.

Sankey for Building Performance Simulation

Found this via utsapocalypse. The Sankey diagram is originally from the article ‘Preliminary Investigation of the Use of Sankey Diagrams to Enhance Building Performance Simulation-Supported Design’ by William (Liam) O’Brien of Carleton University, Ottawa.

The paper proposes “the outline for a methodology for creating Sankey diagrams to represent energy flows in buildings, with the eventual intent that the methodology be integrated into a software tool.”

The Sankey diagram shows the energy balance of a house for a mid-winter week. Flows are in kWh, total amount 804 kWh. Energy sources/types are from the left (purchased heat, domestic hot water, solar gains), energy consumption and losses to the right (heat loss through windows, ceilings, walls).

Plenty of colors used in the diagram, Sankey arrows glued together from shapes. As the author mentions “the underlying creation process, when performed manually, can be quite complex”.

VisualizeGreen.com Free Sankey Template

Premnath Sundharam from the Visualize Green blog contacted me to draw attention to a Sankey diagram template he has made and that is available for download on his site.

The diagram is for predicted energy intensity for buildings. An Excel template is provided that allows entering the data. You can use this with the free trial version of e!Sankey (registering required). All elements of the diagram and the entry sheet is explained in detail by Premnath. In regard to the unit (KBtu per square foot per year) he says:

Last but not least, kBtu/sf/yr is becoming the universal (US) unit of communicating building energy consumption. This unit is called the EUI – Energy Use Intensity and since it is a simulation of how your building will perform, it is called PEUI – Predicted Energy Use Intenisty.

Good stuff, Premnath! Thanks for making this available to everyone.

Note November 2011: Also look at Premnath’s Energy Story here.

Energy optimized heating system

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.