Critique my Micro Swamp Cooler Design

[5280MeV]

I had an idea for a micro swamp cooler design that would prevent me from having to get a 5-gallon bucket, cool a single person in a small 2-man tent with shading, and require a very tiny amount of stuff to take on a plane. It is based on using a 2.5 gal water suitcase rather than a bucket.

I have two variants, one using capillary action to draw up water and the other using an actual pump. I think that this could work for me, so I thought I would share.

If you are a playa HVAC engineer and have tried this before or know that it won't work, please let me know. It is cold and humid here in Tennessee, so it is hard to test it out at the moment.

frogbird cooler.png

[FIGJAM]

First, I would mount the fans to the container so that ALL the air is forced to draw through the damp material, whatever that may be.

Second, the damp material has to be fairly well sealed around the edges so that all the air has to pass through your damp "pads".

Our biggest challenge was getting fans that pull enough air through to make for an effective unit.

Good luck with your design!

[lemur]

only 113 on this day... highest i saw in the tent was 119 this past year


it cools down a good 6-10 degrees in my tent when i upen the doors and 'windows' and let the air flow through..





we dont need no stinkin a/c!


(this message brought to you by high fructose corn syrup)

edit: (And duracell)

[theCryptofishist]

Okay, I'm taking up a pool. One dollar gets you in. Name the hour, PST, when this gets moved to the Cooling subforum.
Mods are not permitted to take part, for what I hope are obvious reasons.

[FIGJAM]

If your taking up a pool, you won't need a cooler!

[5280MeV]

First, I would mount the fans to the container so that ALL the air is forced to draw through the damp material, whatever that may be.

Second, the damp material has to be fairly well sealed around the edges so that all the air has to pass through your damp "pads".

Our biggest challenge was getting fans that pull enough air through to make for an effective unit.

Good luck with your design!

Thanks - this helps a lot. I wasn't sure if airflow or mesh surface area was a limiting factor. If I am attaching the fan to the container, then I may as well attach everything to the container - I could actually use the screws for the fan to hold the cloth up.

Worst case I would just use the suitcase in place of the bucket and go with the traditional design, but I am really curious to see if capillary action can pull water fast enough to match evaporation.

Does the air really need to go through the damp pads versus over it? Maybe a laminar setup with multiple cloths perpendicular to fans on either side of the case, forcing air through a channel.

I am going to play with this and post pics if it works.

[FIGJAM]

The problem with any material that will wick water fast enough is that it may not be porse enough to allow for air flow.

If it's not porse enough, it may also glog with dust.

If you want to just bring the parts for a bucket cooler, I can bring a predrilled bucket for you.

[DustHand]

I have always thought this would be an easy, and reasonably inexpensive solution. Plus, very efficient and reliable.

Use an evaporative humidifier, and modify it.

http://www.google.com/products/catalog?q=Hunter+32200+2-Gallon+Evaporative+Humidifier&um=1&ie=UTF-8&tbm=shop&cid=4669187189076533753&sa=X&ei=pR0PT4mHLojl0QG2oLSvAw&ved=0CIoBEPMCMAI

The fan will probably run on AC, so if you don't have an inverter or generator, you would have to find a DC replacement fan.

The only other thing you would need to do is find a bit of flexible ductwork to attach to the air outlet on top, and run that into your tent or whatever. Simply fill the reservoir when it goes dry.

I have seen the replacement filters for 6 bucks, for when it gets clogged full of playa dust.

There are many other types with bigger reservoirs, etc.

I like this idea because the tightness from water to inlet through the pad and out is about as good as you can get, and you won't spend any time fiddling. And they are pretty cheap, too.

[Eric]

Nudged over to "Keeping Cool" in Preparation.

[5280MeV]

The problem with any material that will wick water fast enough is that it may not be porse enough to allow for air flow.

If it's not porse enough, it may also glog with dust.

If you want to just bring the parts for a bucket cooler, I can bring a predrilled bucket for you.

Thanks! If all my suitcase experiments fail, I will send you a message.

[BlackRockCityPimp]

pretty fawkin awesome idea. i like to reuse the suitcase water too. i usually end up just using it for my wash basin. if i hadnt already copied figjams box cooler...

if your gonna use fabric or towel cutting into strips will help.

[5280MeV]

i usually end up just using it for my wash basin.

That is a really awesome idea - saves me space on the plane and will work better than the dinky little tupperware that I brought last time. Thanks!

[BlackRockCityPimp]

i usually end up just using it for my wash basin.

That is a really awesome idea - saves me space on the plane and will work better than the dinky little tupperware that I brought last time. Thanks!

cutout just like your swamp cooler on the side. also good for a foot soak.

[5280MeV]

I changed this design to have the air flow along the pieces of cloth rather than through them:

viewtopic.php?f=56&t=33263&hilit=work+in+progress&start=600#p781397

The crazy thing is that I could actually test this today in Tennessee, seeing as it is 105 degrees and 21% humidity.

I put my two man tent in the sun and it was 115 degrees inside. In the shade it was 100. With my micro-swamp cooler it dropped to 95, but the air coming out of the cooler was 90.

After I finished I realized that the fans were only drawing 180 mA of current, when they should draw 480 mA. I was using 8AA rechargables, so I was really only giving them 9.6V when they wanted 12V.

I think that it would work better if it got the proper power, and I think that if I made a second one the whole thing would actually do fairly well in a two person tent. I also have not yet sealed the vents in my tent, which may make a difference.

[FIGJAM]

These pics were taken when it was 8% humidity.

[Canoe]

... I am really curious to see if capillary action can pull water fast enough to match evaporation...

The issue is likely to be: will it lift the water up the entire height of the cloth?
And, if it does, will it continue to do so, or will the evaporation be limited to a smaller wet section near the level of the water.
Capillary cloth lift is typically limited to 1". I did some tests with capillary matting, meant for lifting water for gardening, both for watering and for cooling from latent evaporation (like the swamp cooler).

Capillary fed. I just did a test on capillary mat. Dry mat hanging vertical into water lifts the water 1.25", with another 3/8" damp. Priming the mat with water keeps it wet up to 3.5" for several hours, but eventually falls back to barely more than the dry mat could pull up when placed into water. Dry mat passes air surprisingly readily. Fibres may be too close together to provide maximum water surface area for the air flow for the footprint of the mat. Suspicious that this may not be a suitable replacement for the blue fiber mat. Could be used in a horizontal wet filter configuration, but you'd need a much larger footprint than the designs that we already know work well.
But, cap-mat could lift water out of a reservoir onto the blue matting, but unlikely to have enough water flow to keep up with the job. You'd have to have lots of matting to feed the top of the blue mat to ensure enough flow to avoid dry sections. Don't know if you can have enough for it to work...

I changed this design to have the air flow along the pieces of cloth rather than through them...

Then you're dependent on the latent evaporation from:
- the wet cloth to only the dry incoming air that flows next to the cloth, with some of the moisture it absorbs spreading to the bulk of the air that's by-passing the cloth,
- the turbulent flow of the air along the cloth to expose the dry incoming air to wet fibres.

If the air had to pass through the cloth, the incoming air would be exposed to a lot more wet fibres, for more surface area for latent evaporation. This is why the blue fibre mat works so well. Lots of surface area for the volume it occupies, while providing air flow. There's little line-of-sight for the dry air to flow through without having turbulence put it into contact with the surface of the water on the fibres.