Evaporative cooling for metal buildings

[Steve B]

I am about to complete a metal building project. I had shown to me a HVAC
study where large industrial sized buildings were cooled by a surface
application of plain water, sprayed on with regular PVC lines and regular
lawn sprayers. The drainage was collected with gutters, and recirculated.
A 25 deg. F drop was possible using this method.

Has anyone here ever used flowing water on a metal building, or any style of
structure as a coolant? I'd like to hear of your experiences.

Steve

[gregz]

The only thing I could think of was crawling on top of shiny metal shed
roof. Must have been at least 130 degrees. It's been shown, an inner
separated reflective layer can reduce interior heat by a large amount.
That's with sunshine.

The roof would still be 105 by your estimation. Probably less. I think that
idea sucks.

Greg

[Home Guy]

Steve B wrote:

> I had shown to me a HVAC study where large industrial sized
> buildings were cooled by a surface application of plain water,
> sprayed on with regular PVC lines and regular lawn sprayers.

There was a thread here in this newsgroup a few months ago (during the
hottest few weeks of this past summer) pertaining to exactly that
concept - spraying water on roofs to cool the attic space and/or prevent
heat transfer into the structure.

Some links were posted to some home-made solutions and commercial
suppliers of roof evaporative-cooling systems.

Mineral buildup on spray equipment and on the roof will be your biggest
problem if I recall correctly.

Recirculation of excess water captured from the roof will probably not
be a good idea, as you will have a problem cooling it prior to
re-application - unless you can spray, capture and cool so much water at
such a high rate that you can keep the roof temperature close to ambient
air temperature.

[Steve B]

"gregz" <ze...@comcast.net> wrote in message
news:1644346515342056853.4...@news.eternal-september.org...

Sorry I didn't explain more fully. Temperature reduction was up to 25
degrees from ambient air temperature, not from surface temperature of
anything left in the direct sunlight.

HTH

Steve

[Steve B]

"Home Guy" <Ho...@Guy.com> wrote in message news:4EB33773...@Guy.com...

I pay $100 per year for "ag water". A fresh supply of cool water will not
be a problem. A filter is $100. Sanitizers are dirt cheap, too. I'm just
going to have to get it up and running and fine tune from there.

Steve

[Stormin Mormon]

Really works differently in different climates. In NYS
(downwind of the great lakes) the humidity is high, and we
simply have NO swamp coolers around. I have only seen one in
my life, and that's the one I helped take apart.

You'd have to see what your climate and humidity are like.
That will help a lot, to tell if it's worth the trouble.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.


"Steve B" <ste...@gmail.com> wrote in message
news:4vFsq.68101$sq4....@news.usenetserver.com...

[Vic Smith]

On Thu, 3 Nov 2011 18:26:31 -0700, "Steve B" <ste...@gmail.com> wrote:
>
>I pay $100 per year for "ag water". A fresh supply of cool water will not
>be a problem. A filter is $100. Sanitizers are dirt cheap, too. I'm just
>going to have to get it up and running and fine tune from there.
>

Sounds like a no-brainer. Evap cooling works well, and best in dry
air. Works in even not so dry air.
Copying canvas canteen covers, I used to cool a can of Coca-Cola
by wrapping it in a wet rag and sticking it in a blower vent in the
boiler room of my ship.
Took it down from 100 to about 60 degrees even using humid 90 degree
Caribbean air. Powerful air flow though.

--Vic

[Malcom "Mal" Reynolds]

In article <4vFsq.68101$sq4....@news.usenetserver.com>,

I'll defer to the other answers, but here is a consideration: with proper
venting you should get some cooling of the roof, but if you water the roof, the
interior of the building MAY get cool enough for you, or not. It may be best to
use a really large Evap Cooler as that will not only pump in cool air, it will
actively circulate the air which may be worth more to you than just a cool roof

[harry]

Evaporative cooling only works where the humidity is low.
There are many different designs. But if the water don't evaporate,
there is no cooling effect.
If the water comes from a hard water source you get limescale build
up on the evaporator.

[DD_BobK]

As someone else posted, there was another recent thread on this (maybe
for your "roof" spanning the gap between two ocean contianers?)

Any way.... your idea will work, just a mater of getting details
right.
Good surface coverage would be important.

As HBub mentions, mineral build up could be an issue.
At your cost of water, it's not worth recycling but the runoff could
be reused as ag water for something so as not to totally waste it.

here is a place

http://en.wikipedia.org/wiki/Rutt's_Hut

that I saw water roof cooling more than 50 years ago. must have work
cuz they used it.
NJ is not particularly dry so you've go a huge advantage.

Water's advantage is due to ~1000 btu/lb of evaporation energy (8340
btu/gallon)
Evaporate 10 gallons per hour and you've got ~7 ton equivalent cooling
(of course that's on the outside) but that's still a lot of heat not
trying to get into the building.

Forget the naysayers & go for it.
If you started with a small section you could do some exerpeiemnts.

Measure (cheap water water meter) the amount of water applied.
Collect the water that runs. The difference would be close to the
amount evap'd.

Gallons x 8340 btu/ gallon would give oyu evap energy.

12,000 btu / hr ~ 1ton A/C

If you did you run for less than an hour you'd have to extrapolate the
"hour's worth of water".
Also it would be best to not start the experimental measurements until
the water was running for a while
and the metal surface was at its "running temp".

All these back of the envelop calcs are not highly accurate but
considering the cost of electricity, water & spinkler system parts,
they good enough to make the effort worth a try.

Would rust be a concern with the building?

cheers
Bob

[Bob F]

Which brings to mind the possibility of interior condensation if both methods
are used together.

[Steve B]

"Bob F" <bobn...@gmail.com> wrote in message
news:j918f7$k7o$1...@dont-email.me...

Condensation and rusting are a real issue. The reason is to provide an
inside welding and work area, and block the wind, so an exchange of air
would defeat the cooling idea. With water cooling, the air exchange would
not have to be as great. A dedicated welding area would be nice, too, and
exhaust less air. It will have two 8x8 doors on each end, so opening them
up somewhat will take out the welding smoke. But also the cooler air. This
might come down to a combination of both evaporative coolers AND surface
watering, or one of the other. Just have to get this monster built and try
it out. Summer heat is brutal, and winter winds are just about as bad.
Then there's the blowing sand ........

Steve

[Oren]

On Fri, 4 Nov 2011 08:55:09 -0700 (PDT), harry <harol...@aol.com>
wrote:

>Evaporative cooling only works where the humidity is low.

Any humidity at 45% or less the "swamp coolers" (evaporative) work
well. Widely used in the desert.

>There are many different designs. But if the water don't evaporate,
>there is no cooling effect.
>If the water comes from a hard water source you get limescale build
>up on the evaporator.

Systems are shut down for winter. In the spring they get a service
cleaning, inspection or repairs made.

[Malcom "Mal" Reynolds]

In article <AbWsq.22315$G32....@news.usenetserver.com>,

Just spitballing, but if you had a roof mounted variable speed fan and put lots
of vents around the bottom edge of the building, you should be able to control
the wind. If you added pads and water to the vents, you could get the cooling,
ventilation and control the winds

[Steve B]

"Oren" <Or...@127.0.0.1> wrote in message
news:m5c8b7pbeh9kk6e73...@4ax.com...

And, as any desert rat kid learns when they reach the age of being able to
do yard work for their old man are a ROYAL F'N PITA clean up job. You
forgot changing those cheesy shredded rope pads, too.

Steve

[aldacosta]

About 40 years ago my father put lawn sprinklers on the tin roof of our dairy barn. It worked very well. Some neighbors saw what my father did and stopped by. When the walked inside the dairy barn and felt how much cooler the did the same at their dairy. Our dairy was in Ontario California and the temperature would react in 110 and hotter in the summer.

--
For full context, visit https://www.homeownershub.com/maintenance/evaporative-cooling-for-metal-buildings-668937-.htm

[Ralph Mowery]

In article <16c0243a2e8de911$1$4039542$4646d813
@news.newsgroupdirect.com>, 35d27c2659153a7b...@example.com
says...

>
> About 40 years ago my father put lawn sprinklers on the tin roof of our dairy barn. It worked very well. Some neighbors saw what my father did and stopped by. When the walked inside the dairy barn and felt how much cooler the did the same at their dairy. Our dairy was in Ontario California and the temperature would react in 110
and hotter in the summer.
>
> --
>
>

I may have to try that on my new metal carport type garage.

[Snag]

Use that spray mist tubing stuff . I've done this and unless the
water is finely atomized and uniformly distributed you'll waste a lot .
Next summer it may not matter as much . I'm installing a pump in our
well to use the water on our garden and I think it'll be much cheaper to
pump than to use city water .
--
Snag
Let's Go Brandon !