Does Humid Air Rise or Sink?

[Drguano]

Last summer I bought a used tower humidor with an old Cigar Oasis Magna humidifier. I removed the foam brick and used it with distilled water and water saver beads until Xmas. The Magna was on the bottom shelf and kept the lower area around 65-67%. The r/h readings were lower at the upper shelf where the temp is a bit warmer. There they were  around 59-60%. I keep digital hygrometers on each of the shelves and switched them around to be sure the hygrometers were roughly accurate. In December, the h started dropping to about 54% on the top shelf and I decided to get a new Magna 2.0. 

I installed the new one and now the h is 90% + on the lowest shelf where the new Magna sits (right where the old one was), 87% on the next shelf, then 70%, 61% and 57% 0n the top shelf.

I was wondering if it was air flow being blocked by boxes so I emptied the 2nd shelf up and the left side of the remaining shelves. Not much change overnight.

Then I cannibalized the top of the old Magna and have it on the top shelf to run as an aux fan. After an hour, h on bottom is 87% @ 63F, then (moving upwards) 82% @63F, 78% @ 65F, 61% @ 70F, 61%@ 68F and 55% @ 70F on the top shelf.

I am wondering how to get lower h on the bottom shelves and higher h at the top.

I have the sensor/controller mounted on the back wall on the top shelf.

My reading says humid air rises.

Any thoughts?

 

[RazorbackFan]

I can only speak for my own humidor and my own experience, but humidity rises within my humidor, for sure. 

[Monterey]

Humid air has more water vapor in it and is heavier.  Therefore, humid air sinks, not rises.   This assumes no fans or other things that alter how air is in your humidor.

[HarveyBoulevard]

9 minutes ago, Monterey said:

Humid air has more water vapor in it and is heavier.  Therefore, humid air sinks, not rises.   This assumes no fans or other things that alter how air is in your humidor.

That is 100% incorrect...

At the same temperature and pressure, humid air rises.

[LLC]

Humid air rises and if the top of the humidor is warmer than the bottom it will read lower RH even though though the moisture content may be the same.


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[Customsfan]

Thank you guys.  I always learn through these postings.

[GotaCohiba]

I have a very similar setup and have added 4 lbs of RH beads to keep things balanced out

That said.....

I just received my wife of 27yrs blessing to place an order for an Aristocrat from Bob

She added, be sure and get exactly what you want -  she has no idea what she did

[Drguano]

50 minutes ago, GotaCohiba said:

I have a very similar setup and have added 4 lbs of RH beads to keep things balanced out

That said.....

I just received my wife of 27yrs blessing to place an order for an Aristocrat from Bob

She added, be sure and get exactly what you want -  she has no idea what she did

I am getting closer to ordering one myself. Enough screwing around! Still, I am wondering why the difference in humidity from bottom to top.

[TBird55]

She added, be sure and get exactly what you want -  Speaking from experience, after you decide on  the size of your Aristocrat, order one that is larger than you think you need. 

[Guest Nekhyludov]

1 hour ago, GotaCohiba said:

She added, be sure and get exactly what you want -  she has no idea what she did

If my wife said that, I would take it to mean "enjoy this one, 'cuz it won't happen again." 

[Monterey]

2 hours ago, HarveyBoulevard said:

That is 100% incorrect...

At the same temperature and pressure, humid air rises.

Yup.  I stand corrected.  I've been wrong for a very long time!

 

[GotaCohiba]

33 minutes ago, TBird55 said:

She added, be sure and get exactly what you want -  Speaking from experience, after you decide on  the size of your Aristocrat, order one that is larger than you think you need. 

I was aiming for the. M plus, but I’m ordering the MXT 26.5

 

[stogieluver]

24 minutes ago, GotaCohiba said:

I was aiming for the. M plus, but I’m ordering the MXT 26.5

 

I have the M Plus.  Never thought I would fill it up.  Now, I'm playing Tetris.  I took everyone's advice and ordered one larger than I thought I would need.  Good advice. 

If I had it to do all over, I would go with a taller unit, not deeper.  You store boxes two and three deep, and can't find what you're looking for without unloading the front row.

[stogieluver]

At the request of @GotaCohiba, I'm posting a photo of my M Plus. 

The point being, with all four shelves two boxes deep, you have to remove the front row of boxes on each shelf to find the box you're looking for.  I know, First World problem.   

[GotaCohiba]

That’s a ton of storage space, awesome looking cabinet

Thanks for the photos 

[Mossome]

6 hours ago, HarveyBoulevard said:

That is 100% incorrect...

At the same temperature and pressure, humid air rises.

I’ve heard this several times before, so explain why my bovedas in the top shelf exude moisture and dry up while those on the bottom shelf are absorbing excess moisture and puff up. Every time I see someone concerned about different readings on gauges, they always have a higher reading on the lower gauge. I’m not saying you’re wrong, again I’ve heard it many times, it just goes against what I’m seeing in real life. 

[HarveyBoulevard]

I agree that it does not seem logical to me but check out a good chemistry/physics book and you will see that water molecules are lighter than air molecules so in fact, humid air rises.  Crazy I know...but don't take my word for it.  It is easily researched and explained far better than I can.

As far as 'real life', other conditions may impact the conditions in/around a humidor other than humid air v dry air.

I'm not a scientist...but I did drive by a Holiday Inn last night.

[SCgarman]

3 hours ago, stogieluver said:

At the request of @GotaCohiba, I'm posting a photo of my M Plus. 

The point being, with all four shelves two boxes deep, you have to remove the front row of boxes on each shelf to find the box you're looking for.  I know, First World problem.   

I in fact remember when you first joined this forum. And you had returned from a Cuba vacation with what? 2 or 3 boxes? You have definitely upped the ante over the past few years eh? Did you go from working at a bank to owning it? LOL

[Mossome]

2 hours ago, HarveyBoulevard said:

I agree that it does not seem logical to me but check out a good chemistry/physics book and you will see that water molecules are lighter than air molecules so in fact, humid air rises.  Crazy I know...but don't take my word for it.  It is easily researched and explained far better than I can.

As far as 'real life', other conditions may impact the conditions in/around a humidor other than humid air v dry air.

I'm not a scientist...but I did drive by a Holiday Inn last night.

Yeah. I took it to the Google machine. It makes sense. Avagadro’s number, atomic weights, and  whatnot. It’s just weird. 

[gcman68]

Dru,

I have the exact same humidor and use the Avallo Acumonitor with a canister on each shelf (I only have two top shelves which I felt would better for storage and air circulation) and it includes fans that circulate air as well which I attached above the canisters.  I also get the same thing with the humidity being higher in the lower part of the humidor but not by much. I store my humidor in a semi finished basement so the temp can vary 4-5 degrees from top to bottom (colder on the bottom I assume due to the cold floor) and the fact that the humidor (mine at least) had an opening for a light at the very top that I believe wasn't sealed well. There is still a little discrepancy in humidity levels for me but once I sealed off the hole in the top better the top level works better. I believe had I not had a canister on that shelf and lots of beads it would have been a bigger discrepancy.  I don't think I helped in your question except I will say your not alone!  

[Monterey]

16 hours ago, HarveyBoulevard said:

I agree that it does not seem logical to me but check out a good chemistry/physics book and you will see that water molecules are lighter than air molecules so in fact, humid air rises.  Crazy I know...but don't take my word for it.  It is easily researched and explained far better than I can.

As far as 'real life', other conditions may impact the conditions in/around a humidor other than humid air v dry air.

I'm not a scientist...but I did drive by a Holiday Inn last night.

I have the same problem.  I have 7 of the Newair CC-300's with gauges at the top, middle, and bottom.  In practical sense, my bottoms numbers tend to be slightly higher.  Hence my original statement.  Then Harvey schooled me, so I googled it.  And he was right.  So purely from a science standpoint, Harvey is right.  But for whatever reason, it seems the opposite happens inside of humidors.   Those darn Cubans!

[Drguano]

I moved the tower from the exterior wall to an interior wall and the temp on the bottom shelf is now 63 F and the top shelf eat 69F. The humidity on the bottom shelf has dropped to 80% and the top shelf is at 57%. I have a ton of dry 65% beads down there and still can't get the humidity to drop. I just added another 1/2 lb of beads and will see if things stabilize overnight. Maybe I need to design a system of rotating shelves that will cycle my boxes from top to bottom and back again to maintain a consistent level of humidification...

[prodigy]

I think you need more airflow. The spread shouldn't be that drastic, between both temp and humidity.

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[Fugu]

Prodigy is right here. It's all basically a matter of air circulation and mixing. A quite typical flaw with these tower-like humidors. As it appears now, this is much more a temperature issue (indicating poor mixing), the rH coming in second. A temp-gradient of 7°F (4°C) as reported is huge. Before bothering about humidity your first concern should be about how to minimize temperature gradients. A perfect humidor is showing uniform temperature top to bottom. Only once you got that sorted out start to think about humidity.

Should that turn out difficult, an option perhaps to consider would be making two separate humidors out of that single one (= divide horizontally). Two separate smaller units are more easily controlled. Comes at the cost of some storage space.

[Drguano]

I thought about this and removed the fans from the top shelf (the fan unit from my original Oasis Magna) and put a tray of moist beads to provide humidity. The sensor control unit for the new Mahan is up there. The moisture from the beads is raising the humidity up there and reducing the out put from the Magna on the bottom shelf. The humidity is higher on top (58%) and down to 71% on the bottom shelves. My auxiliary fan kit will arrive tomorrow so I can better adjust airflow. By tweaking airflow, providing another source of humidity (I might get a Hydra unit) on top and adjusting the sensor for the Magna, I think I am on the way to regaining control of the situation. Temp on the bottom shelf is now 63F and the top shelf is 68F.