Large-Scale Misting

[masonicboom]

I'm looking for ideas and wisdom on large-scale misting operations.

My camp runs a big misting tent using fans. We're curious if there are other good ways to deliver mist. If you have experience, please share.

We found that those perforated hoses tend to clog with dust and drizzle water rather than misting.

[BBadger]

You could buy some misting nozzles, many of which are anti-drip and cleanable. Then pump filtered water through it to reduce the chance of clogging.

[dbdave]

Hello - I was also interested in mid-scale misting, ala Mystopia, and I can see how to setup the fans, I was just wondering about the logistics of supplying all the water? How much does each nozzle burn (gallons per min) and how best should I store and replenish the water supply (assuming using the Bman water company).. How does one set this up, how big large a cistern should we use? Any helpful tips like that would make for a nice misty burn this year... thanks, David (with Baaahs)

[FIGJAM]

When I was looking into this, I found out each nozzle uses a half gallon per hour...………..and did something else.

[Token]

Misting done right can be very impressive for cooling large open air spaces.

The key to it is good design and getting the right droplet size for flash evaporation. - the sweet spot where all the water evaporates before reaching the skin.

To do it right without big loud fans, you want high water pressure and micron sized water drops. Ideal droplet size is in the 20 micron range, smaller is better.

The problem with misting is that it is not very portable nor as cost or energy efficient as it seems.

To design for minimal water use you have to run high pressure. High pressure for misting is 500 to 1000 PSI.

When using a 0.12 mm nozzle at 500 PSI you will run ~ 0.5 gallons per hour (GPH) on that nozzle.

As a comparison, a 0.3 mm nozzle (smallest nozzle for household pressure of 40-80 psi) will drink 1.1 GPH and have big sloppy droplets ( 40+ micron).

A 10 nozzle 500 PSI system will thus drink 5 gallons per hour and cool a good size area. Nozzles are spaced every 2 feet in typical systems so this gives you a 10 -12 foot wall of cool air you can work with.

Now, that 500 or 1000 PSI pump may set you back a cool $500 - $1K just in base cost and then chug 500-1000 W of power. So you need a sturdy generator as well.

So, a 55 Gallon drum could give this hypothetical system 10 hours of runtime water, two days worth if you time it well.

To do it right or at scale, entry level cost for this will be thousands (notice the plural).

But, once you get past the capital investment (pump, generator, lines) it scales well and extra nozzle and line are relatively cheap.

Now getting 500 or 1000 gallons of water there ... it adds up cost wise.

[Papa Bear]

Now getting 500 or 1000 gallons of water there ... it adds up cost wise.

Sure does. In fact, once you hit that range it can be worth it to own the water containers, haul them out to Gerlach during build week to fill, and then bring them back in instead of contracting for water delivery. You do need transportation beefy enough to haul a few tons of water and someone willing to spend part of their build week doing the run, but if you have that anyway then the savings can be significant.

That's exactly what we do, for a similar quantity of water. If we do find ourselves going through water faster than expected by Wednesday or so, we may arrange for a smaller fill on playa to bridge the gap - nobody wants to do a Gerlach run during event week.

[Molotov]

Your water supply must be scrupulously clean to avoid potential growth of Legionella. The Centers for Disease Control and Prevention warn that people can get Legionnaires’ disease or Pontiac fever when they breathe in small droplets of water in the air that contain the bacteria. Cooling misters that spray a fine mist allows water droplets to be inhaled into the lungs which can potentially contract Legionella if the conditions are right.

More info here