
The Paris Compressed-Air Power Network (2018) - camtarn
http://www.douglas-self.com/MUSEUM/POWER/airnetwork/airnetwork.htm
======
tdeck
Paris also used to have an incredibly extensive network of pneumatic mail
tubes:
[https://www.cix.co.uk/~mhayhurst/jdhayhurst/pneumatic/book1....](https://www.cix.co.uk/~mhayhurst/jdhayhurst/pneumatic/book1.html)

as did several other cities (NYC, Philadelphia, Prague, ...) to a lesser
extent:
[https://en.wikipedia.org/wiki/Pneumatic_tube](https://en.wikipedia.org/wiki/Pneumatic_tube)

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pranjalv123
Another interesting method for power transmission in the early days of
industrialization was the line shaft
([https://en.wikipedia.org/wiki/Line_shaft](https://en.wikipedia.org/wiki/Line_shaft)).
These were used only for a single factory, not for a whole city, though. You
can see these if you go visit old textile plants in New England, for example.

~~~
dredmorbius
Also hydraulic accumulators:

[https://en.wikipedia.org/wiki/London_Hydraulic_Power_Company](https://en.wikipedia.org/wiki/London_Hydraulic_Power_Company)

[https://99percentinvisible.org/article/running-on-water-
the-...](https://99percentinvisible.org/article/running-on-water-the-
hydraulic-system-that-tapped-the-thames-to-power-london/)

~~~
camtarn
Amusingly, modern hydraulic accumulators of a different sort may still have a
role in power generation. I'm working on a couple of wave generator projects
where the waves pump hydraulic rams, storing pulses of pressure in hydraulic
accumulators, where it's then used to drive a generator at a more constant
speed.

~~~
dredmorbius
Intresting, though wave power is a minusculy small overall altrnative energy
source with massive capital feqirements. There are better options to pursue.

Pumped hydro is ... after a fashion ... a vastly more appropriate hydraulic
accumulator, as is CAES.

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ekingr
I stumbled upon one of its remaining manhole covers a few weeks ago, which led
me to discover about this network.

I have been living in Paris for 10 years but never knew this existed before.

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datdata
I loved this. Really interesting. Some of the French translation is a little
off IMO. I would say that "usine" probably translates better as "plant" or
"factory". "Particuliers" means individuals in this context. So these are
supplies to individuals rather than businesses (theatres, cafes etc). I really
enjoyed it nonetheless

~~~
rjnl87
I found the same with the translations, I was looking for a contact/feedback
option to tell them, but couldn't find any way to contact the site owner.
Throughly enjoyed this anyway! PS, I believe "usine" translates to "Oven" or
"furnace", at least that's what I've learned in high school (French wasn't
really my strong suit though), which makes sense in that's where the coal is
burned to generate heat>pressure>power.

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tonyarkles
Unrelated, but as soon as I saw the domain name I got excited. This is indeed
the same Douglas Self that has published a ton of interesting information on
audio amplifiers. Really fascinating info all over his site, both about
electronics and other random things (like the compressed-air power network)

~~~
peteri
He's one of my favourite ex-coworkers. His knowledge of audio electronics is
superb and his thoughts on subjectivism are worth a read.

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dmolony
_In contrast, the worst that could happen with compressed air was a burst
pipe; this would not be a good thing to be standing near, but since the pipes
ran through the sewers the chance of this was very small._

Even more reason to avoid standing near a burst pipe.

~~~
walshemj
Actually its a burst reservoir that is nasty.

I was told at college that in the event of the small full service (electricity
water and air on tap) lab block's compressed air reservoir blowing it would
take most of the building with it.

Steam is even worse BTW

~~~
dsfyu404ed
But reservoirs pretty much never burst unless relief valves fail or oil gets
into them.

(inb4 a bunch of hand wringing about rusty compressor tanks, those just leak
and are generally harmless)

~~~
dublin
This is what the ASME was formed for - to create standards for safe pressure
vessels. At the time it was founded, there was just over one steam boiler
explosion a week in the US...

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steve19
Does anyone know what pressure came out at the consumers end? The article
mentions a 10 bar (145 psi) steam engine. Most modern air tools require about
90 psi.

I wonder what the efficiency of the system was. I am sure a lot of air leaked
all over the place.

~~~
6nf
Compressed air is pretty terrible at energy efficiency. The main source of
energy loss is due to heat at compression. When you compress air, a lot of the
energy ends up just increasing the temperature of the compressed air and this
is then quickly lost in the transmission process.

~~~
steve19
Of course! I forgot about the loss during generation. I have had to deal with
my fair share of overheating compressors.

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yason
No mention of drying the air in the network. They had to have good driers to
prevent water from entering the network or elaborate number of venting points
to remove water from the low points of the network. Anyone know more?

~~~
m-app
I'm no expert on this, but could this be the reason of the confusion in the
picture titled "Section of the Quai de Gare usine: 1892", where the author
mentions "A = drying channels (not sure what that means- they look like sewers
in cross-section. May just mean 'drainage')"?

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kome
This website is awesome. Internet should be like this.

~~~
tomatotomato37
I really enjoy the section of the site on engine designs; some of them are
even animated, like this bit:

[http://www.douglas-
self.com/MUSEUM/POWER/unusualICeng/axial-...](http://www.douglas-
self.com/MUSEUM/POWER/unusualICeng/axial-ICeng/axial-IC.htm)

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leandron
Previous discussion here:
[https://news.ycombinator.com/item?id=19442938](https://news.ycombinator.com/item?id=19442938)

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userbinator
Whenever I read about ancient technology like this, I wonder if any of the
equipment and infrastructure survives today.

~~~
Bayart
You usually end up with overlapped left over portions of old networks. Paris
is a good case study for that, the entire underbelly of the city is an
nightmarish amalgamation of tunnels and pipes.

~~~
hef19898
You have that in basically every city after after a certain period of time. In
Europe even more as some settlements, like Paris, go _way_ back. The city I
live apparently can be crossed undergroung in everything ranging from Roman
relics to whatever was added. The historic center at least

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dublin
This is one of the best HN articles I've red in a long time - a fascinating
look at a very well-developed infrastructure system in one of the most
technologically advanced cities of its day.

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baud147258
Today I learned something about the city where I'm living. Thanks HN!

