Martin Fierz
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martinfierz.bsky.social
Martin Fierz
@martinfierz.bsky.social
Professor at University of Applied Sciences, Co-Founder at naneos particle solutions, interested in all things to do with energy and efficiency.
During my postdoc year there, I once wanted to order a bottle of compressed Nitrogen (cost: a few dozen bucks). It took 3 weeks to get it..... I ended up buying stuff like that myself in order to get any work done! To be fair, that is over 20 years ago now.
January 5, 2026 at 12:20 PM
Great stuff and some nice memories of my Postdoc in Honolulu over 20 years ago.
December 26, 2025 at 12:28 PM
Der Link den Sie gepostet haben hatte nur 6 Häuser angeschaut. Zudem noch ein Mix von Luft- und Erdwäre-Wärmepumpen die man nicht vergleichen sollte.

Ich bin Riesenfan von WPs und betreue 4 Systeme in unserer Familie; aber wenn man den Effekt der Gebäudequalität nicht sieht, dann stimmt was nicht.
December 18, 2025 at 12:21 PM
Das sind 6 Beispiele, keine Studie. Wenn dann noch das neuste Haus aus unerfindlichen Gründen eine extrem hohe Vorlauftemperatur aufweist, dann ist der Befund halt so wie er ist - aber das sollte nicht so sein.... Vermutlich sind die WPs da einfach schlecht eingestellt.
December 17, 2025 at 10:03 PM
Das ist schon wahr, aber einfach nicht üblich. Im Normalfall hat man schon einen Zusammenhang zwischen Gebäudestandard und Jahresarbeitszahl.
December 17, 2025 at 9:43 PM
Etwas überraschend daher dass das Alter der Häuser kaum eine Rolle für die Effizienz spielt?
December 17, 2025 at 9:40 PM
Lifting from 15 to 80°C will make for a rather inefficient heat pump though...
December 14, 2025 at 10:22 PM
What specifically? The problem with district heating is that you need high temperatures, which makes heat pumps inefficient. In modern houses, you can usally run the heating at 30°C, making them far more efficient.
December 3, 2025 at 8:39 PM
What if the data center moves in a few years? What if data centers get more energy efficient?
Also, district heating is often inefficient because very high temperatures are used (70°C+).
December 3, 2025 at 12:02 PM
September 24, 2025 at 1:25 PM
Führend im Greenwashing? Extrem energieintensive Aktivitäten werden nicht plötzlich grün nur weil man sie mit angeblich grünem Wasserstoff macht....
September 21, 2025 at 2:00 PM
Unfortunately, we have lots of Mercedes G Class on our streets in Switzerland to which your arguments would also apply. But driving a bigger car somehow seems to attract some people :-(
September 14, 2025 at 6:32 AM
Are there good/intuitive explanations for the large changes over short time periods?
August 25, 2025 at 1:30 PM
...when measured by particulate mass. If you look at particle number and surface area (likely the most health relevant metric) it's very different.
The weight of something doesn't tell you much about its toxicity!
August 23, 2025 at 11:28 AM
@hannahritchie.bsky.social you write "Google says that its median text query uses around 0.24 Wh of electricity. That’s a tiny amount: equivalent to microwaving for one second, or running a fridge for 6 seconds" which implies 144W for a fridge.

For comparison, my fridge uses over 10x less!
August 23, 2025 at 6:04 AM
not anonymous at all:
July 30, 2025 at 7:24 AM