Sylvain Miermont @miermont@qoto.org

Time for a short #bookReview 📖

I finished reading #TheDawnOfEverything by D. #Graeber and D. #Wengrow.

It's quite a long book that took me way more than a month to go through, but worth the read and the last fifth of the book, post conclusion, is notes and references that can be skipped without losing too much. Overall very interesting, I warmly recommend it, even if some chapters were going a little too deep into the archeological record for my non-specialist tastes.

It was illuminating, specially as I had previously read #GunsGermsAndSteel by J. #Diamond and #Sapiens by Y. N. #Harari, both very popular books, and both adopting a very deterministic view of past human history.
I'm not 100% convinced by the interpretations of Graeber & Wengrow, but they appear to make a real honest effort at understanding our past, they base their reflections on recent archeological records, and present a much more nuanced "story of the human civilizations" than the previously cited books.

The book doesn't really provide any actionnable advice on how we should collectively go forward, but at least it tries to set the record straight on what was previously attempted ... with various level of success.

Did you know that #CO2 can be used as a #refrigerant gas in #heatPumps? And that it's very efficient at it.
It requires significantly higher pressures than typical refrigerants gas but it doesn't require a chemical plan to fiddle with fluorinated products, and that seems to be a huge plus. Also, it is cheap, guaranteed not to have any undesirable effect we might discover later, non-flammable, non-toxic and has a GWP of 1.

With a COP above 3, the global #efficiency of a combined-cycle methane power plant + transmission loss + point of use COP gives a higher efficiency than burning the methane directly even in the best furnace money can buy.
And we know very well how to store hot water, so spreading daily peak heat demand without massive *electricity* storage is much more feasible.

This weekend it's

Mastodon, will probably be a tad slow for the coming days. Please post reasonably, and give everyone some time to settle.

Maybe you can repost, summarize, or reflect on the best posts you've seen on Twitter and other sites. Doing a compilation of some of the greatest stuff we've seen elsewhere is a good way to set the tone.

#Japan imports a lot of liquefied #methane (CH4), also called LNG.

Since 2013, this country hosts the single largest #LNG storage tank in the World: 60 meters high, with a useful diameter of 70 meters, it stores 250'000 cubic meter of cryogenic liquid, for a mass of 105 metric kilotons of CH4.
If that #CH4 was vented, that would be the equivalent of 8.5 megatons of #CO2 equivalent in GWP20 (1.5 times the #Nordstream leak).
https://www.youtube.com/watch?v=wDOqUFaPXsY

Because the storage capacity scales to the cube of dimensions, but thermal loss scales with the square of dimensions, physics favors such huge tanks. And because the soil is cooler than ambient air most of the year, there is also a benefit to having those tanks underground.

In total, Japan has a LNG storage capacity of 73 times this single tank.