Author Topic: The holy trinity of proper temp, humidity, air velocity.  (Read 3598 times)

Offline ArnaudForestier

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The holy trinity of proper temp, humidity, air velocity.
« on: October 10, 2014, 11:22:14 PM »
Go to 3:19.  This is seriously sweet.

I'm trying to accomplish something like this with a DIY ductsock pipeline and ultrasonics placed into the air stream.  Needless to say, mine is not as successful.  :o
- Paul

John@PC

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #1 on: October 11, 2014, 12:02:25 AM »
Fascinating video of which I didn't understand a word (well, maybe one or two; where are subtitles when you need them :)).  I did watch to the end and saw what you were talking about with the duct vapor injection system.   90%+ RH is tough with A/C cooling without condensation somewhere (and hopefully not on your precious cheeses). 

Offline ArnaudForestier

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #2 on: October 11, 2014, 12:06:09 AM »
Yeah, John, you're sure right.  I can get RH and Temp perfect, but airflow is ridiculously fast.  Or good flow and temp, but UH fog drops out and condenses on the floor.  Trying to finesse this has been the occupation of the last couple of weeks!
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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #3 on: October 11, 2014, 12:34:32 AM »
Trying to finesse this has been the occupation of the last couple of weeks!
Add that to the multitude of your occupations in the past ;)!  I will say this based on what I've learned:  If you're using A/C with or without a CoolBot you will lower %RH every time it runs - at 85% plus RH and 55F it only takes a surface of 51F (dew point at those conditions) to condense moisture.  Apparently your floor is the "cold spot" so that's where it condenses.  It's also possible that your controller is over humidifying during the A/C's cooling cycle and then when it shuts off you have excess humidity.   In your case Paul you may want to invest in a temp / humidity data logger to really see what's going on in there over time until you find the right solution.

Offline ArnaudForestier

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #4 on: October 11, 2014, 02:45:47 AM »
Thanks John, that's really helpful.  I actually stayed in the cave a good part of today under different scenarios, and just visually watched the fog pattern in the cave, as well as monitored the readouts on temp and RH...with and without the fabric sock, different humidifier placement - and you bet, your controller fans mounted on top of the UHs, to blow the fog up and over!  The antagonism between the cooling cycle and the RH was dramatic...especially with the cooling piped "naked," just the elbow leading to what would be the duct, RH went from 92 to 83 in short order.  It climbs back once the cooling kicks off, but it does take a few minutes.  Your idea of a log is a great idea.  One of my hygrometers has a min/max function, and I about flipped - as high as 67F and as low as 42....which makes no sense, as I know the temp is pretty spot on and the basement is well insulated.  I'm hopeful that's a complete historical record, since the thing turned on, and not the last 24 hours...at any rate, thanks, that's a great idea. 

So - my ignorance is showing - but how do they get such a perfect stream, as in that video?  Pav had the thought that the place was likely exceedingly well insulated, if not fully subterranean, so cooling need is likely minimal (active system, but a very low cooling load).  Makes perfect sense.  That air flow and incredible, blue-smoke of humidity...man, it would be nice to know more how this is done.  Any thoughts, yourself?
- Paul

Offline awakephd

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #5 on: October 12, 2014, 03:54:43 PM »
Paul,

How large is your A/C for this room? One thought is to greatly oversize the A/C -- I don't know if this will work in this application, but one of the issues when sizing an A/C for a house or other building is that too large a compressor tends not to dehumidify the air sufficiently for comfort. Too large a compressor runs too short an amount of time; the right-sized compressor runs longer, pulling more moisture from the air. Since you want moisture ... maybe too large is the ticket.

Another thought: Is there a way to get even cooling without the airflow? For example, in my wine-fridge-turned-cheese-cave, there is no fan. Not sure if that can be scaled up to a whole room, at least not affordably. Hmm -- what about having the A/C cooling a thin concrete block wall on one side, with the cheese cave on the other -- the cave is cooled by the cool walls, not by direct air flow.

As you can see, I am just thinking aloud -- I'm glad to help you spend your money on finding a good solution! :)

Andy
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Offline ArnaudForestier

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #6 on: October 13, 2014, 06:27:08 PM »
Hey Andy, thanks.  My A/C is actually HUGELY oversized - 14250 btu for a 216 c.f. cave, a really tiny thing as caves go.  And right, it's nice to get the thing to work so little.  Unfortunately, I may have vastly overshot.  I've tried all kinds of tweaking as the last thing I want to do is remove this a/c, pull and refrigerate my existing cheeses, and install a more appropriately sized A/C (I really blew this one - don't know what I was thinking except I was thinking on the same lines as you....just kind of went wild with the idea :o).

All ideas welcome!  I don't know how efficiently radiant cooling in this way would work, but it's an interesting notion.  More and more, I'm leaning towards getting out of the air game for cooling.  Whether above ground or below ground, an exceedingly well insulated space, icewater pipes, and the only air, engineered air for positive flow and makeup air, NH3 removal, etc.  It seems to me the best money spent is on insulating - whether buried underground and soil, or above-ground with high R-factors.  Thanks goes to Pav for talking this out with me, he's some phenomenal ideas, as usual.

Thanks, buddy.  Cheese to you.
- Paul

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #7 on: October 13, 2014, 09:23:42 PM »
For example, in my wine-fridge-turned-cheese-cave, there is no fan. Not sure if that can be scaled up to a whole room, at least not affordably.
A lot of wine coolers (and portable electric coolers) are cooled using solid state devices called Thermoelectric Cooling or TEC modules.  If you haven't played with one of these things they are fascinating little mini heat pumps.  You apply voltage and one side heats enough to boil water and the other cools enough to freeze; switch polarity and the heating / cooling flips.  The drawback is that they are limited in their cooling output.  As far as I know the most efficient and lowest cost method for cooling mid-range sized caves is a window or portable A/C (with or without a CoolBot) then pumping in the moisture to counter-balance the de-humidification.  I do have a small bathroom with no windows that we don't use that much (about 250 cu. ft) that I could convert and do a lot of neat tests but there is just one problem (rhymes with Life :().

ps.  I am actually running some tests with different humidification systems in the bathroom cave at room temperature as my (rhymes with Life) is out of town for a few days.  Will post results.

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #8 on: October 14, 2014, 02:08:16 PM »
John, I don't want to interfere in your experiments, but ... IMHO you are treading on very dangerous ground!

My wine-fridge-turned-cheese-cave uses a traditional compressor, but yes, TECs are very cool. (Or very hot, depending on which side. :))

Speaking of dangerous ground ... has anybody tried digging an old-fashioned root cellar to use as a cheese cave? I do have a fairly large back yard, which mostly gets used for mowing. :) Of course, I'd have to figure out exactly where the septic leach fields are -- definitely would not want to put the root cellar there!!
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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #9 on: October 14, 2014, 10:21:52 PM »
John, I don't want to interfere in your experiments, but ... IMHO you are treading on very dangerous ground!
Wait, what??  Am I in danger of contracting Ebola :o? (sorry, something I should kid about :-[)  Not sure what dangerous ground as I've worked with TECs extensively and know their idiosyncrasies which is why I would never recommend them for a cheese cave any larger than, well, a wine cooler.
Of course, I'd have to figure out exactly where the septic leach fields are -- definitely would not want to put the root cellar there!!
Totally agree there: THAT is dangerous ground (while recognizing the unintentional pun  ;D).

Offline awakephd

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #10 on: October 14, 2014, 11:42:53 PM »
No, I was not thinking of experiments with TECs ... more like experiments with sacred rooms in the house while spouse is away. Being in the middle of a lengthy bathroom remodel (three months ago: this will only take a week or so, honey!), I am rather sensitive to this dangerous ground ... :)
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Offline ArnaudForestier

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #11 on: October 15, 2014, 01:38:56 AM »
There's a reason I'm relegated to the basement.  My beloved grew tired of 1/2 bbl brewery and cellar, full lab, aquaria,  and alpine cheesemaking .... in our bedroom, along with most livable corners elsewhere.  I'm this close to being on a plane with our mutts.  Course, they always understood. ;D
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Offline pastpawn

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Re: The holy trinity of proper temp, humidity, air velocity.
« Reply #12 on: October 15, 2014, 05:57:53 AM »
There's a reason I'm relegated to the basement.  My beloved grew tired of 1/2 bbl brewery and cellar, full lab, aquaria,  and alpine cheesemaking .... in our bedroom, along with most livable corners elsewhere.  I'm this close to being on a plane with our mutts.  Course, they always understood. ;D

OT:  You keep fish? I have a reef.  We definitely should talk!
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