Green Building Forum - CO2 & humidity Tue, 19 Dec 2023 05:09:11 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241299#Comment_241299 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241299#Comment_241299 Tue, 24 May 2016 14:08:16 +0100 djh
You can see a single spike of humidity to 87% and of CO2 to 1020 ppm. That was when I took a shower with the door closed (the door frame has a slot to allow ventilation air past). You can see how fast the readings come back down as soon as I opened the door. My wife took a shower shortly afterwards but she leaves the door slightly open so there isn't another spike.

CO2 climbs a bit overnight and then starts coming down after I get up - I don't use the ensuite in the morning. There's another blip when my wife gets up.]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241301#Comment_241301 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241301#Comment_241301 Tue, 24 May 2016 14:36:01 +0100 Simon Still CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241303#Comment_241303 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241303#Comment_241303 Tue, 24 May 2016 14:44:05 +0100 djh Posted By: Simon StillWould 1 person in a small room be enough to spike CO2 that much?
You got me! I had the Leicester football team and the elephants from Whipsnade in there with me. :boogie:

The room is 2 m square and 2.4-3.2 m high.]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241305#Comment_241305 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241305#Comment_241305 Tue, 24 May 2016 15:35:13 +0100 SteamyTea I may be talking out my rear end, or that may be the problem.

Our old mate Damon HD did some research into this, I think the data is on his website.]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241309#Comment_241309 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241309#Comment_241309 Tue, 24 May 2016 16:45:25 +0100 djh
Background CO2 outdoors is apparently 380 ppm or so.
Background CO2 in our house seems to be about 450 ppm.
450 ppm = 810 mg/m³ I think.

A person breathes out about 1 kg CO2 per day (which doesn't contribute to global warming since it is produced from plants that were eaten). Which is 694 mg/min.

My shower seems to have taken 11 minutes in total (i.e. door was closed for that period) so the total CO2 exhaled is 7639 mg.

The volume of the room is about 12 m³, so that's 637 mg/m³ of extra CO2
810+637 = 1447 mg/m³ or 803 ppm

So either the room is smaller or I was breathing heavily :cry: Or my arithmetic has gone astray.]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241310#Comment_241310 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241310#Comment_241310 Tue, 24 May 2016 16:47:51 +0100 djh Posted By: SteamyTeaJust randomly thinking here, but could the CO2 be coming out the hot water. Warmer water can hold more CO2
Well it can but it didn't - ten seconds before it sprayed out the shower head, it was cold water in the main.

I may be talking out my rear end, or that may be the problem.

Our old mate Damon HD did some research into this, I think the data is on his website.

DHD did research on your rear end? :devil:]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241319#Comment_241319 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241319#Comment_241319 Tue, 24 May 2016 18:12:15 +0100 Ed Davies
Are you sure? Normally gases come out of solution as water warms. One of the global warming feedbacks is considered to be increased atmospheric COâ‚‚ as the sea water warms, isn't it?

Playing with these equations [¹] in gnuplot shows a decreased solubility with increased temperature for CO₂ over the range 0 to 50 °C unless I've messed up.

[1] https://en.wikipedia.org/wiki/Henry%27s_law#Temperature_dependence]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241327#Comment_241327 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241327#Comment_241327 Tue, 24 May 2016 21:12:13 +0100 willie.macleod
Sensor placement is crucial and avoiding putting them in direct line of folk breathing next to them. In a very small room you would need to be even more careful.]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241332#Comment_241332 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241332#Comment_241332 Tue, 24 May 2016 22:00:13 +0100 SteamyTea Posted By: Ed DaviesAre you sure? Normally gases come out of solution as water warms.Your dead right, I realised as I was driving to work I had it the wrong way around.]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241336#Comment_241336 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241336#Comment_241336 Tue, 24 May 2016 23:23:33 +0100 djh Posted By: willie.macleodCO2 sensors will spike with someone standing next to them and show similar readings to what you are getting.
Indeed. That became obvious as soon as I turned the thing on. The ensuite was the third room I got to so I'd had a bit of practice.

Your wife probably completely ignored the thing and you probably looked over at it because you were aware it was there and breathed in its direction a few times.....

Sensor placement is crucial and avoiding putting them in direct line of folk breathing next to them. In a very small room you would need to be even more careful.

Good advice. I'm fairly sure the data is realistic. It has a real-time display as well as logging so it was easy to see any induced spikes.]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241398#Comment_241398 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241398#Comment_241398 Wed, 25 May 2016 21:55:41 +0100 fostertom Posted By: Ed DaviesAre you sure? Normally gases come out of solution as water warmsBut wouldn't warm water be a better solvent, and if prevented from off-gassing (enclosed in pipe) could be carrying more CO2 until released to fresh air?]]> CO2 & humidity http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241399#Comment_241399 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14291&Focus=241399#Comment_241399 Wed, 25 May 2016 22:18:23 +0100 Ed Davies