
Office buildings should run like spaceships (2017) - jdkee
https://www.wsj.com/articles/why-office-buildings-should-run-like-spaceships-1507467601
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sbierwagen
>The solution, he says, is an HVAC system that dynamically responds to both
carbon-dioxide levels and levels of airborne particulate matter, pumping in
fresh air while filtering out pollutants. It’s remarkably similar to the kind
of air-circulation systems that NASA uses—on spaceships.

Ah yes. The NASA spaceships that pump in fresh air from outside the spaceship.

More seriously, I just bought the parts for a homebrew HRV, (
[https://en.wikipedia.org/wiki/Energy_recovery_ventilation](https://en.wikipedia.org/wiki/Energy_recovery_ventilation)
) in the hopes of improving the CO2 concentration in my apartment, which is as
bad as you'd expect: [https://bbot.org/co2/](https://bbot.org/co2/)

~~~
sxp
Nice CO2 graph. What did you use for the sensor & logging system? I bought an
off-the-shelf CO2 monitor to tell me when I should open a window, but I can't
extract the sensor readings from it. Any recommendations on good sensors
compatible with standard home measurement systems? I have a Sense Hat for my
RPi that logs temp & humidity and would like to add CO2 to it if possible.

~~~
sbierwagen
It's a SCD30 talking to a flask.py script that logs the data with sqlite.
Graph is done with plotly.js. All hacked together quickly, none of it working
terribly well. Never tried to hook it into a home automation system.

The SCD30 carrier board I used was one of the Seeedstudio grove units:
[https://www.digikey.com/products/en?mpart=101020634&v=1597](https://www.digikey.com/products/en?mpart=101020634&v=1597)
Seeed says it's a 3.3/5V compatible unit, so you could even use it with your
Pi if you buy a Grove base hat to add to your stack. I'm using it at 5V, so I
don't have any direct experience with that configuration, though.

In my experience the SCD30 autocalibration is worthless, so put it outside and
manually set it to a plausible number. I used
[https://www.pmel.noaa.gov/co2/story/Space+Needle](https://www.pmel.noaa.gov/co2/story/Space+Needle)
as a reference. I think the Grove library ran it at a 2 second poll rate by
default, which results in a substantial amount of sensor self-heating. (It
draws 75mA while reading co2, since it's a spectrometer) This gives you a
tradeoff between accuracy and data staleness, I just run mine at 20s and point
a fan at it. If you build it into an air handling unit, which is its intended
application, that's not a problem.

~~~
chx
> It's a SCD30 talking to a flask.py script that logs the data with sqlite.
> Graph is done with plotly.

[https://html9responsiveboilerstrapjs.com/](https://html9responsiveboilerstrapjs.com/)

> 2\. How do I install this? Um... are you stupid or something? Just
> attackclone the grit repo pushmerge, then rubygem the lymphnode js shawarma
> module – and presto!

Here I am with twenty years of a programmer career, more than 15 years of that
with open source (just to illustrate I am not unfamiliar with hacking) and ...
uh ... I open the balcony door from time to time and air the bedroom before
going to sleep. I am too old for y'all.

~~~
sbierwagen
I mean, I hadn't used flask since 2014, and had never used sqlite, plotly or
an esp8266 (as a wifi transceiver) before. The project was intended as a
learning exercise for playing around with those tools. Someone who just wants
a CO2 sensor would buy
[https://www.amazon.com/dp/B0784TZFRW/](https://www.amazon.com/dp/B0784TZFRW/)
, which isn't much more expensive than my pile of components and has way more
functionality; and someone who was interested in the messing with technology
aspect would want to figure it out for themselves. There's maybe 200 lines of
code total, in the entire project. Someone who wasn't as determined to wander
into blind alleys as I was could do it in a weekend.

------
keenmaster
Article: [https://outline.com/9P3z32](https://outline.com/9P3z32)

Also here's a description of the "spaceship HVAC" on NASA's tech transfer
site, I wonder how expensive it would be for an office building:
[https://technology.nasa.gov/patent/LEW-
TOPS-93](https://technology.nasa.gov/patent/LEW-TOPS-93)

