How quick does water evaporate?
January 12, 2009 12:21 PM   Subscribe

Would putting some 5 gallon buckets of water in our server room lessen the need to add water to the existing humidifiers?
posted by khaibit to Science & Nature (17 answers total)
 
I'm guessing that the evaporation rate of the water from the buckets of water is going to be way lower than the humidifier pumps out. Possibly even so low as to make little impact whatsoever.

I'm going to say no, but I'm sure someone will give you the science of it.
posted by Solomon at 12:23 PM on January 12, 2009


Science aside, do you really want open containers of water in your server room? I mean I know that a 5 gallon bucket isn't EASY to tip over, but it's certainly not outside the realm of possibility...
posted by fusinski at 12:24 PM on January 12, 2009


Response by poster: This is clearly just a thought experiment.
posted by khaibit at 12:31 PM on January 12, 2009


This strikes me as a spectacularly bad idea.

1) You will be carrying five gallons of water, in a bucket, to and fro through your server room. This is a room which has tremendously expensive equipment that does not like to get wet.

2) It will grow algae and mold, unless you change it out every other day. Which means you are carrying five gallons of water, in a bucket, to and fro through your server room.

3) You will have five gallons of water, in a bucket, standing around where people will trip on it, in your server room.

Humidifiers do what a free-standing bucket of water does, put water vapor into the air, only faster, cleaner, and without the potential of drenching your equipment with five gallons of water due to operator error.
posted by Slap*Happy at 12:33 PM on January 12, 2009 [2 favorites]


In that case, I think it might break the guidelines.

To answer your question, though: it would help, but not much. To build on the, uh, wisdom of Solomon, above, a five-gallon bucket doesn't have a whole lot of surface area for evaporation.
posted by box at 12:36 PM on January 12, 2009


"Thought experiments" do not make good AskMes.

That said, adding any moisture to the room will lessen the frequency with which you re-fill the humidifiers, whether than saves you a few minutes or a few days is anyone's guess.

If it's really a problem, and not just random chatfilter, buy a larger humidifier.
posted by wfrgms at 12:39 PM on January 12, 2009


Response by poster: This is actually a problem, given the low temperatures lately we have had to add water both in the morning and the evening. This was suggested, and I was hoping someone would have something to back this up or shoot it down. That is all.
posted by khaibit at 12:42 PM on January 12, 2009


Hilarity or tragedy will ensue. Five gallons of water near electrical equipment? Well, are these people your enemies? 'cause I can get behind vengeance.
posted by jadepearl at 12:45 PM on January 12, 2009 [1 favorite]


The amount of water isn't nearly as important as it's surface area. A broad shallow dish with a gallon of water would be much more effective than a 5 gallon bucket of water. Even better would be a broad shallow dish with damp sponges in it. It could make a significant difference in the room's humidity, if it's large enough.
posted by 517 at 12:46 PM on January 12, 2009


This really does sound like a major accident waiting to happen. Not recommended.
posted by Chocolate Pickle at 12:54 PM on January 12, 2009


Best answer: Well ...

If I recall correctly, part of what a humidifier does is to blow air over the water so that you get convective transport as opposed to diffusive transport, which is what you would get if you had air standing still over the water (water is being transported through random movement of molecules). As a rule of thumb, convective transport is approximately ten times faster than diffusive transport, so (given the other surface area considerations), you're looking at something at least ten times less effective than a humidifier.

I personally think that this sort of solution (given the danger of open topped containers lacking secondary containment) is one of those penny-wise, pound-foolish sorts of things.
posted by Comrade_robot at 12:59 PM on January 12, 2009


It depends on how big your humidifier container is right now, but:

If adding more water to your humidifiers in a problem you could certainly use a 5-gal bucket with a lid and two holes in it. One hole is for air, and the other hole is for a tube that will lead to your current humidifier basin.

If the bucket has a lid, the spilling issue is a little less critical. This will keep you from swapping the water so frequently (assuming that 5 gal is substantially larger than your current humidifier basin.

If you wanted to get really fancy, you could pipe a water line straight in, and have a ball float system (like in a toilet) that will allow water in to the basin whenever it is necessary.
posted by milqman at 1:17 PM on January 12, 2009


I'd say the first step is to take your servers off of the ground and to place them on top of cinder blocks or bricks or something. I use the Twilight books for this purpose. As long as they are sitting on the ground they in danger of being immersed in water from the plastic bucket accident. Also remove any boxes of raw pasta, baseball cards or metallic sodium.

But seriously, you could enhance the bucket(s) of water by adding a rolled up sheet of diffusing material from a swamp cooler. They are just fibrous mats of some kind and draw moisture like crazy. I think they are $4.
posted by cockeyed at 1:35 PM on January 12, 2009


The obvious comparison is to look at the surface area of the evaporative components of the existing humidifiers, compared to the surface area of the bucket, and then add in multipliers as appropriate to deal with the convective vs diffusive issue. This would be hard without knowing details about the humidifier, but I would guess that any reasonably-sized humidifier will have a wick-type element that's probably hundreds of times the area of a 5gal bucket. Maybe thousands, if you count the area of all the individual fibers in a 'mat' type one.

But I think there might be an easier way, if you wanted to experiment. (And who doesn't like experiments, right?) You could just measure the water consumption of the humidifiers, and then in a separate but similar room, measure the rate that water evaporated from a bucket (perhaps over the course of a week or so). Some algaecide, available from anyone with a pool or hot tub at home, might be a good addition. Alternately you could throw some chlorine bleach in there to inhibit mold/algae, but it will leave your office smelling like a public pool and might throw off the results since it evaporates fairly quickly itself.

You would then know what the maximum possible additional humidity that the bucket would add, since you measured the evaporation out of the bucket when it was in a room without the big humidifiers. If you put it in the server room, because the ambient humidity will be higher, they're not going to give up as much.

My gut feeling is that when you find this upper limit on the bucket system's performance you will discover that it's too low to bother with. Anyway, this would be my approach: one fire-and-forget experiment to establish the upper bound and then decide whether it's even worth continuing. Easier, IMO, than trying to calculate it theoretically. (But then I am an experimentalist at heart; this "arts and crafts" approach would no doubt be derided by any decent theoretician...)
posted by Kadin2048 at 7:48 PM on January 12, 2009



I work in several data centers, admittedly in a much more humid country, but why do you have humidifiers in your data center?
posted by lundman at 9:04 PM on January 12, 2009


Ah, spot of googling found http://searchdatacenter.techtarget.com/news/article/0,289142,sid80_gci1261265,00.html#

triboelectric effect seems to be the only real reason, and that's still unsure. Interesting, maybe I'll start monitoring the humidity to see if there is any correlation.
posted by lundman at 9:19 PM on January 12, 2009


Why not just buy an additional or higher-capacity humidifier?
posted by fantabulous timewaster at 5:24 AM on January 13, 2009


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