OT : Rooftop sprinklers for evaporative cooling

[bulldogcountry1]

I have a 30x48 metal building that is insulated, but no AC...yet.

I have a chemical tote that I catch rainwater in to clean various things. For a long time, I have been interested in evaporative cooling. I would like to use an electric (possibly solar) pump to spray the water in my tote through sprinklers onto the metal roof to cool my shop.

Anyone have experience with this? I know the key is to only use enough water so that it doesn’t drip off the roof. It all needs to evaporate to be the most efficient. I have plenty of free water, so the only expense would be to pump that water through the sprinklers in short increments during the hottest part of the day.

 

[cowbell88]

Soaker hose. Run it down crown of building. Sprinklers use to much water.

Hardware store or tractor supply for a pump.

 

[Augustus McCrae]

I have a 30x48 metal building that is insulated, but no AC...yet.

I have a chemical tote that I catch rainwater in to clean various things. For a long time, I have been interested in evaporative cooling. I would like to use an electric (possibly solar) pump to spray the water in my tote through sprinklers onto the metal roof to cool my shop.

Anyone have experience with this? I know the key is to only use enough water so that it doesn’t drip off the roof. It all needs to evaporate to be the most efficient. I have plenty of free water, so the only expense would be to pump that water through the sprinklers in short increments during the hottest part of the day.

I’m sensing an “Engie explains evaporative cooling “ article in SPS Magazine in our near future.

 

[turkish]

I have a 30x48 metal building that is insulated, but no AC...yet.

I have a chemical tote that I catch rainwater in to clean various things. For a long time, I have been interested in evaporative cooling. I would like to use an electric (possibly solar) pump to spray the water in my tote through sprinklers onto the metal roof to cool my shop.

Anyone have experience with this? I know the key is to only use enough water so that it doesn’t drip off the roof. It all needs to evaporate to be the most efficient. I have plenty of free water, so the only expense would be to pump that water through the sprinklers in short increments during the hottest part of the day.

What are your expectations? Define success for this effort. A tote worth of warm water ain’t gonna do a thing.

 

[RocketDawg]

No experience implementing it, but experience with the effects of it. Northwest Jr. High in Meridian was built in the early 1960s - one story, flat roof with tar and white gravel. There was no air conditioning. We went to school well into June in those days and it would get hot. They'd put sprinklers on the roof during the school day, and it probably helped some, but it was still really hot inside. The humidity is too high in Mississippi for evaporation to help much.

 

[jethreauxdawg]

What Rocket said

The humidity is too high in Mississippi for evaporation to help much.

Due to our humidity, it won’t evaporate enough to have a big impact. It’s probably better than no evaporation but not sure the juice is worth the squeeze

 

[Mobile Bay]

If the thermodynamics were favorable lots of places would do it.

Few places use this.

That's enough to tell me it is not worth doing.

 

[dawgman42]

This is not a viable cooling method in the southeast. Now, when I lived in Phoenix, swamp coolers worked well up to about 30% humidity. Direct radiant heat plus the humidity will yield a very negligible effect.

 

[aTotal360]

You need a thermochemist...

 

[garddog]

Better off putting a fan to pull heat out near the roofline.

 

[SheltonChoked]

I have a 30x48 metal building that is insulated, but no AC...yet.

I have a chemical tote that I catch rainwater in to clean various things. For a long time, I have been interested in evaporative cooling. I would like to use an electric (possibly solar) pump to spray the water in my tote through sprinklers onto the metal roof to cool my shop.

Anyone have experience with this? I know the key is to only use enough water so that it doesn’t drip off the roof. It all needs to evaporate to be the most efficient. I have plenty of free water, so the only expense would be to pump that water through the sprinklers in short increments during the hottest part of the day.

Contrary to everyone else on here, I think it will work for cutting the heat on the roof. The outside of a roof in the summertime gets very hot. An unpainted metal roof will get to about 140F. That metal will radiate heat down inside. If the roof has a reflective heat paint, reduce that to 120-130F. Using water will cool the peak of the roof to the water temperature or lower (down to wet bulb).

Swamp coolers don't work well for people in the southeast. But using the water to soak up the solar heat of the roof will help reduce the surface temp.
Most don't do it as the water or power is better used in another way. But if you have the water, and solar power the pump, shouldn't be an issue.

I know a horse barn here that does it in the summer here. It helps. Use a soaker hose. and let it drip off the side a little.

 

[JesterB]

Safety Coatings in Foley, Al. Uses a system that has perforated pvc pipe at the ridge and recycles water with a gutter to rain collector. They were a customer of mine years ago so I’m not sure if they still have it or not but the maintenance man there was all about it at the time. He claimed an 8-10 degree temp drop.

 

[jumpdawg]

This was also used in Vicksburg at Batesville Casket's sawmill. They were a customer of mine and it was the early 2000's, so I don't remember the specifics......but I remember them being happy with the results.

 

[MagnoliaHunter]

Don't know if it's doable for a big building, but in the summer we put a tarp over our camper about a foot off of it and it made an incredible difference in the inside temperature. A/C didn't have to work nearly as hard to cool. Get as light a color as you can find.