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.
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
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.
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
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 ........
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
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
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
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
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
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?
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.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.