Tag: solar

Visualizing Internal and External Heat Flow

This post on the Transsolar ‘Green & Sexy’ blog features two Sankey diagrams. The “climate engineers” at Transsolar use them to model heat flows inside a building based on outside temperature and solar radiation.

No absolute values are given in these demo Sankey diagrams, but one can still get a general idea by observing proportions. Flows are color-coded with solor radiation in yellow, convection in blue, and heat losses in red.

The second Sankey diagram shown is a timeline made 24 frames – one per hour over a full-day. As the outside temperature rises and solar radiation increases around noon, the inside temperature and cooling demand increases.

(via tumblr)

Sankey diagram timeline by Transsolar

The authors explain:

“These Sankey diagrams allow us to see the proportion of how much energy is hitting the facade, how much energy is being radiated into the walls, how much energy is being convected into the air, and how much heating or cooling is actually needed to maintain an acceptable indoor air temperature. The animation is the first example we’ve ever seen of a Sankey diagram that represents the dynamic, ever-changing relationship of heat flows in a building with time.”

Sankey Diagram Solar Panel System

From Dr. Sanjay Vashishtha at Firstgreen Consulting blog comes this Sankey diagram on energy output of a photovoltaics (PV) system. The article on ‘Estimation of Solar PV System Output’ dates back to 2012.

Simple unicolor left-to-right diagram with losses branching out vertically to the bottom. At every step energy efficiency in percent is shown, leaving 65% of the primary solar radiation input as power at meter. Losses have a stronger emphasis due to arrow spikes.

Abundance of Solar Energy

In most parts of Europe, Russia and Northern a partial solar eclipse is observed today. People can feel how temperatures drop and dusk seems to begin even though the day has just begun… Time to remember that the sun powers our planet.

This Sankey diagram from the GEA 2012 report (Global Energy Assessment – Toward a Sustainable Future, Cambridge University Press, Cambridge UK and New York, NY, USA and the International Institute for Applied Systems Analysis, Laxenburg, Austria) page 773 shows that the “amount of solar energy available on Earth (estimated at 3.9 million EJ/yr) is many times the present human energy use (~528 EJ in 2009)”.

Process Heat from Solar Power

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.

March:

July:

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!

Block Type Sankey Diagram

Another Sankey diagram type I have come across several times are the very compact ‘block-type’ Sankey diagrams. They basically consist of stacked rectangles, like in the below example from Wikiversity dealing with a solar vehicle project. A left-to-right flow orientation is indicated by the arrow heads peeking out of the stack on the right side.


The diagram shows a breakdown or use of the 100% (31.75W) of solar energy (‘globale straling’). The percentage values always refer to the previous block. This one also has a nice color gradient.

Misc Sankey Diagrams Uncommented 04

Found these two Sankey diagram on Wikiversity. I think it was somewhere on one of the sub-pages on the small solar vehicle… They show energy losses at the different components of the vehicle, such as at the solar panels or through rolling resistance. Percentage values.

These diagrams are made up from rectangles and simple arrows. Only straight arrows, no curves. The blue color of the border of some of the thinner arrows adds a strange effect…