cooling your tent or van

Swamp Coolers, Cooler Management, Dry Ice, Misting Systems, and just plain how to beat the heat.
Post Reply
peaceoflove
Posts: 9
Joined: Thu Aug 08, 2013 11:44 am
Burning Since: 2011

Re: cooling your tent or van

Post by peaceoflove » Mon Aug 12, 2013 9:32 am

I should mention that the dome will be covered in black sunshades to block the majority of direct sunlight...helps a little. Last year I taped all the inner seams in preparation of extreme dust conditions, will probably leave it like that minus one upper seam where I can insert a vent if needed. So - box cooler over unicooler? That can be done, was just hoping to keep it simpler but want to do whatever will work best :wink: . Going container shopping today...I'm not opposed to building one of my own BUT I will not actually be the one building it, so that makes it a little tricky. There is a unicooler on p.54 of this thread that looked as though it might work well, but finding a container of that size is a challenge. (think I've read every single post on this entire thread, so many ideas...) We were thinking maybe we could even find an old swamp cooler shell in a salvage yard if we did the box design...will report back. Thanks Figjam and Canoe for the advice...

For fan cover - a piece of plastic or fabric taped over?

User avatar
Canoe
Posts: 3739
Joined: Sun Jul 31, 2011 8:01 pm

Re: cooling your tent or van

Post by Canoe » Mon Aug 12, 2013 9:50 am

> So - box cooler over unicooler? ...
Same fan, same pump, same power source. Box goes on the outside of the shelter, not the inside (but fan is on the inner side so its speed controls are assessable from inside). You cut three holes instead of one, use three vent grills instead of one, and cut three pads and use a little more tubing.

> Going container shopping today...
plastic garbage can, squared

> We were thinking maybe we could even find an old swamp cooler shell in a salvage yard if we did the box design...
Do you have time to modify it to work as well as a box-cooler (sealing of pad for hot air short circuits, air flows & rate, water flow rate vs. side of filter pads, management of water reservoir instead of a plumbed pressurized water source, push vs. pull fan, etc.)?
There are a lot of technical aspects of a successful swamp-cooler that you get to skip even having to know about, let alone solve modifying one to work with a different fan, pump & filter pad, by simply building a bucket-cooler, uni-cooler or box-cooler the way described.

> For fan cover - a piece of plastic or fabric taped over?
The piece you cut out of your container for the fan hole?
Last edited by Canoe on Mon Aug 12, 2013 10:00 am, edited 1 time in total.
Video games are giving kids unrealistic expectations on how many swords they can carry.
.
... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

User avatar
FIGJAM
Posts: 10233
Joined: Thu Mar 25, 2010 10:39 am
Location: apache junction az.

Re: cooling your tent or van

Post by FIGJAM » Mon Aug 12, 2013 10:00 am

I don't know what your budget is, but I looked at a lot of options before building my own.

Fiberglass bait tanks come in a lot of dimensions.

Patio/pool bins is another option if you can seal it.

You can get lexan boxes made to order, but their pricy.
"Don't buy ur Burn...........Build ur Burn!"

"If I can't find an answer, I'll create one!!!"

Fuck Im Good Just Ask Me

User avatar
dragonpilot
Posts: 1648
Joined: Tue May 08, 2007 12:53 pm
Burning Since: 2005
Camp Name: Red Tea Camp
Location: Seattle, WA

Re: cooling your tent or van

Post by dragonpilot » Mon Aug 12, 2013 1:02 pm

FIGJAM wrote:As far as the pump and fan go, if you bought the pump I recommended, it comes with clips to connect to the battery.
Is the pump you recommended the first one on this page: http://www.siliconsolar.com/replacement ... html...but may be too later to order online...I'm heading out next Tuesday! What does HF have in the store that's compatible?

My pump wiring needs to reach about 10' to my deep cycle battery fixed to my trailer tongue...thinking I may need to add some wire (what gauge?).

I'm going to use my Harbor Freight solar pump as my primary pump to conserve battery power...but I noticed that the little solar panel needs to be pointed directly at the sun to run at full power...which means having to constantly adjust it. We'll see how it goes, but I'll have the battery pump as a backup.
Don't bore your friends with all your troubles. Tell your enemies instead, for they will delight in hearing about them.

User avatar
FIGJAM
Posts: 10233
Joined: Thu Mar 25, 2010 10:39 am
Location: apache junction az.

Re: cooling your tent or van

Post by FIGJAM » Mon Aug 12, 2013 3:37 pm

That company stopped selling the pumps.

Now they are here or on ebay.

https://www.greenlivingforu.com/dc-subm ... or-battery
"Don't buy ur Burn...........Build ur Burn!"

"If I can't find an answer, I'll create one!!!"

Fuck Im Good Just Ask Me

User avatar
dragonpilot
Posts: 1648
Joined: Tue May 08, 2007 12:53 pm
Burning Since: 2005
Camp Name: Red Tea Camp
Location: Seattle, WA

Re: cooling your tent or van

Post by dragonpilot » Mon Aug 12, 2013 4:47 pm

Thanks...I'll look around Seattle...too late for shipping unless I pay $$ for faster...

What gauge is the wire I should be using?
Don't bore your friends with all your troubles. Tell your enemies instead, for they will delight in hearing about them.

User avatar
FIGJAM
Posts: 10233
Joined: Thu Mar 25, 2010 10:39 am
Location: apache junction az.

Re: cooling your tent or van

Post by FIGJAM » Mon Aug 12, 2013 6:01 pm

I think the pump wire is 16 or 18.

It's not very big.
"Don't buy ur Burn...........Build ur Burn!"

"If I can't find an answer, I'll create one!!!"

Fuck Im Good Just Ask Me

User avatar
otakup0pe
Posts: 144
Joined: Sat Jan 21, 2012 6:27 pm
Burning Since: 2012
Location: Oakland, CA
Contact:

Re: cooling your tent or van

Post by otakup0pe » Mon Aug 12, 2013 6:09 pm

Do the holes in the side strictly have to be circular ? As long as they are evenly distributed around could they be, for example, rectangular ?

User avatar
FIGJAM
Posts: 10233
Joined: Thu Mar 25, 2010 10:39 am
Location: apache junction az.

Re: cooling your tent or van

Post by FIGJAM » Mon Aug 12, 2013 6:13 pm

Any shape you want!

Someone did a really great one with Man designs all the way around and some kind of rainbow glitter paper! 8)
"Don't buy ur Burn...........Build ur Burn!"

"If I can't find an answer, I'll create one!!!"

Fuck Im Good Just Ask Me

MysticPixel
Posts: 2
Joined: Tue Aug 13, 2013 12:32 am
Burning Since: 2013

Re: cooling your tent or van

Post by MysticPixel » Tue Aug 13, 2013 1:18 am

So I built the bucket cooler as described in the original post. Had to get 1/2" OD x 3/8" ID tubing to fit the pump. Having some issues with the HF pump...

First off, the solar panel on that thing is kind of janky. So I ditched it for now (keeping it as a backup.) The pump wants ~220mA at 7V if I recall (give or take a few mA, I'd have to find my notes.) So I put 23 ohms of power resistors in line (it might be OK with 12V, but I didn't want to fry it to find out!)

Didn't have any #10 wire so I made the holes in the ring by heating a small screwdriver (maybe #12 size equivalent). Made the holes ~3/4" spacing. Problem is, the pump has a really hard time getting an even flow of water out all the holes.

I made another ring with smaller holes, maybe #14 or so (just used a smaller screwdriver.) This is a bit better, but the ring still has to be almost perfectly level to get even flow from all the holes.

So warning... the HF solar pump is probably not a great choice. If I had smaller tubing that might help but I was in a hurry and just wanted one that would mate properly (also that was the only size I could find a plastic T fitting for.)

Going to try that other pump from GreenLivingForU... seems like the extra power will help out. Maybe also spacing the holes out a bit more so it won't lose pressure.

FYI:
got the cooling pad from here http://www.midlandhardware.com/888693.html#.Ugnon3_JJlk it's 28x33", a hair small but I think it should work, haven't cut it yet, I ordered 2 but think 1 should be enough

Also I found the fan in several local stores for ~$30, but DigiKey had it for $17:
http://www.digikey.com/scripts/DkSearch ... ND&cur=USD

User avatar
atomicray
Posts: 186
Joined: Sat Aug 20, 2011 10:34 pm
Location: Texas

Re: cooling your tent or van

Post by atomicray » Tue Aug 13, 2013 6:42 am

The 23ohms and 12vdc...that provides 0.522amps I do believe.

A zener diode in series with a resistor will step the voltage and dissipate the excess voltage as heat, so you will need to be cautious of the added heat aspect. Wired wrong, parallel, this can burn up the diode or drain the battery. Inexpensive yet higher end electronics theory and application I am afraid :(

Your best and easiest bet is to find a cel phone car charger that meets your voltage step...many are in the <13.8in-7.5out vdc range and if you are like me then having a drawer full of old charges is quite likely...though fairly cheap if new.

Best of luck and success with your project!
"Almost nobody dances sober, unless they happen to be insane."
— H.P. Lovecraft

User avatar
FIGJAM
Posts: 10233
Joined: Thu Mar 25, 2010 10:39 am
Location: apache junction az.

Re: cooling your tent or van

Post by FIGJAM » Tue Aug 13, 2013 7:14 am

Don't get excited about the bowl on top as we found that connectors worked better for ducting, but the creativity of the bucket still tickles me! 8)

Image
"Don't buy ur Burn...........Build ur Burn!"

"If I can't find an answer, I'll create one!!!"

Fuck Im Good Just Ask Me

MysticPixel
Posts: 2
Joined: Tue Aug 13, 2013 12:32 am
Burning Since: 2013

Re: cooling your tent or van

Post by MysticPixel » Tue Aug 13, 2013 5:08 pm

atomicray wrote:The 23ohms and 12vdc...that provides 0.522amps I do believe.
If there's no other load, yes, 12V / 23 ohms = .522 A would flow, if I was to put the 23 ohms directly across supply.

But I meant 23 ohms in series with the pump (might have forgotten to mention, sorry.) So it's really more of a current limiter... the same reason why people put resistors in series with LEDs to run them off a 12V PC supply. The pump wants 7V, and it's happy to pull ~0.22A. So, I need to drop that extra 5V somehow. If assume a current of 0.22A through the circuit, what resistance do I need to drop 5V?
5 = 0.22 * R
R = 5 / .22 = 22.7 ohms
Then as you mentioned you gotta take the power aspect... the resistors need to be rated to dissipate the heat. Quick check, P = 5 * .22 = 1.1W (if the entire thing was a single resistor). As an approximation say I break it into 3 x 7 ohms (yes it's only 21 but close enough for now), V over each = ~1.7, P = ~0.37 so I know the usual 1/4Watters aren't gonna cut it. Went to the power resistor box... only things I had that were small enough to make 23 ohms were some wire-wound 10Watters. Sure, why not!
atomicray wrote:A zener diode in series with a resistor will step the voltage and dissipate the excess voltage as heat, so you will need to be cautious of the added heat aspect. Wired wrong, parallel, this can burn up the diode or drain the battery. Inexpensive yet higher end electronics theory and application I am afraid :(
Yeah zener regulators suck for anything over a few mA, because the parts have to handle the worst-case dissipation when there's no load attached. (Had to look those up for a project a few months ago actually.) But that's getting too complicated even... I don't need real precision here. I could, say, take some regular (bigass) diodes, say 6A2-T, and just use those to drop the voltage. Sure, Vfwd varies, but again this isn't precision work, and I know the order of magnitude, which is close enough to tell me each one will drop around 0.65V. So throw 6 or 7 of those in there before the pump, you'll get it down to 7V.

Just wanted to run the entire thing off 12V if I could, I mean if I was bringing 120V into it I'd use a wall wart and be done. Or if I wanted to get exact I'd just wire up an adjustable regulator, heck I have a LM2593 board sitting on my desk, it'll give me anything I want at up to 2A. But I'm just thinking "keep it simple" ;) The HF pump is less than ideal anyways, it was just the only thing I could find locally.

User avatar
TT120
Posts: 1760
Joined: Fri Jun 03, 2011 8:43 pm
Burning Since: 2012
Camp Name: Orphans TOO!
Location: Sacramento, CA.
Contact:

Re: cooling your tent or van

Post by TT120 » Tue Aug 13, 2013 9:12 pm

Or you could wire 2 pumps in series and that would give you 6 volts at each pump and almost twice the pressure of a single pump. You could stack the pumps on top of each other or run them seperately to a single output.

The pump is designed for 7 volts but I bet 6 would run it pretty good and you wouldn't have the heat dissipation issue like with the components you're considering. Much less math too.
Life's a bitch, then you go to Burning Man - Unjonharley
We welcome the stranger, but that doesn't mean we have to like them, nor they us, and that's alright. - AntiM

W6BJD

User avatar
atomicray
Posts: 186
Joined: Sat Aug 20, 2011 10:34 pm
Location: Texas

Re: cooling your tent or van

Post by atomicray » Tue Aug 13, 2013 10:07 pm

Indeed.

Less math and less complex would be best...those resistors will get hot hot hot.
"Almost nobody dances sober, unless they happen to be insane."
— H.P. Lovecraft

User avatar
Drizzt321
Posts: 109
Joined: Sat Jul 30, 2011 1:07 pm
Burning Since: 2011
Location: LaLa Land

Re: cooling your tent or van

Post by Drizzt321 » Wed Aug 14, 2013 5:34 pm

Just getting in on this thread, I'm making a 5 gal bucket cooler based off of the Figjam design. So far so good, and thought I'd stop by and add that I'm using a deep-cycle 65 Ah battery plus a 10W solar panel to charge it up somewhat. Added to that, I'm using a light activated switch with a pot to tune the sensitivity so that I can have it switch on when it's hitting full sunlight so I don't need to use a switch to turn it on/off manually. I'm using http://www.amazon.com/gp/product/B00BLZ93T2, which can serve as a both light activated switch or dark activated switch. In fact...you could use this to turn on your cooler in the morning while also turning off your lights, and then turn the lights back on at night and turn off the cooler! Looks like it'll do 10A @30V, so you can push a decent amount of power through it, or use it to flip a relay that can handle significantly more power if you need.

User avatar
Canoe
Posts: 3739
Joined: Sun Jul 31, 2011 8:01 pm

Re: cooling your tent or van

Post by Canoe » Wed Aug 14, 2013 6:40 pm

Most are running off of a battery they want to last the whole week. An on/off switch doesn't uses any power to do its job.
Cooling your shelter the whole of daylight would be cooling it for more hours in a day than most people will need, as they're out exploring. Uses more water too. When you return, flip the switch and instant cool, with the hot air inside soon pushed all out of the shelter.

So, turn the switch on vs. brushing the dust off the switch sensor so it can turn on...
Let us know how it works out on playa.
Last edited by Canoe on Wed Aug 14, 2013 7:05 pm, edited 1 time in total.
Video games are giving kids unrealistic expectations on how many swords they can carry.
.
... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

User avatar
FIGJAM
Posts: 10233
Joined: Thu Mar 25, 2010 10:39 am
Location: apache junction az.

Re: cooling your tent or van

Post by FIGJAM » Wed Aug 14, 2013 6:48 pm

Plus if the cooler runs dry while you're out, you may burn out the pump.
"Don't buy ur Burn...........Build ur Burn!"

"If I can't find an answer, I'll create one!!!"

Fuck Im Good Just Ask Me

User avatar
unjonharley
Posts: 10302
Joined: Tue Sep 09, 2003 11:05 am
Burning Since: 2001
Camp Name: Elliot's naked bycycel repair
Location: Salem Or.

Re: cooling your tent or van

Post by unjonharley » Wed Aug 14, 2013 7:33 pm

Damn I move slow.. Took four hours to make a Homer bucket cooler..Doped the temp bout 15 degrees in no time..The humiditey is around 100% this evening.. So I put it away for now..Will mount it in the van tomorrow..

User avatar
Dr. Brap
Posts: 36
Joined: Tue Apr 17, 2012 5:56 pm
Burning Since: 2012
Camp Name: Camp Chirp Chirp

Re: cooling your tent or van

Post by Dr. Brap » Wed Aug 14, 2013 7:48 pm

WE BE figJAMMIN!! Yeah buddy! 30 Degree differential! Welcome to the boom boom tent, the nookie time has officially been extended into the afternoon!
I'd post the evidence but I can't seem to figure out how to post pics...help!

I made a few deviations to utilize some things I already had. I didn't want the Costco battery because of the expense and because I'd only use it once a year. I'd then have to buy a trickle charger to store it too.

Here's what I came up with:
Pump, 3.5-9V with USB plug:
I picked this pump because it had a USB plug on it and I've already got a 18Ahr lithium battery pack for charging cell phones. Running it at 5V instead of the max 9V halves the max flow rate and head. As long as you fill the bucket as much as possible you lower the head as much as possible. This tiny little thing is probably giving me about 10 gpm installed in the cooler. I'm using 5/16"id line with a 3/8" tee. I drilled holes 1/2" apart with a 1.5mm bit (similar size to 14ga wire).

Fan: http://www.coolingsurplus.com/index.php ... s&Itemid=8 I bought mine on Ebay for $18 shipped.
I looked at fans for hours and developed these thoughts:
1. I'm Not worried about how loud it is. The playa is plenty loud and I'll probably have ear plugs in anyway. 30dB or 50db I don't care.
2. Pressure seems to be related to fan rpm. The higher speed fans have higher pressures. If you're not picking Figjam's fan, find one with, I would say, RPMs over 4000.
3. Current ratings for fans are all over the place, a low current fan might sound nice 'cause the battery will last longer but are the flow rate and pressure high enough?
4. Fans are only designed to work one way. While you can wire it backwards and just flip the fan, you'll loose about 20% of it's efficiency, or so I've read. Look closely at the fan case and there should be two arrows. One indicates rotation and the other indicates which way the air should blow. Wire the fan to follow these arrows.
5. Ultimately I picked this fan because it had a pretty high pressure rating for the relatively low 1.05A draw.

I used a toilet flange on top that accepts a 4" sewer line. It actually measures about 5" in diameter which matches up pretty close to the 120mm fan. A normal 4" toilet flange is too small for the 120mm fan. I sealed everything up with caulk. I massaged a 4" rubber coupler over the flange and set a flexible, yet ridged, 4" aluminum duct on top. I used a bucket that I already had and bought a lid at Lowes. The lid is flimsy and I later saw a much sturdier food grade lid at Home depot.

I'm running the fan off of an 18Ahr auto jump pack. This probably won't be enough but I have a 12V solar panel that puts out 0.2A I think if I leave the panel plugged in all day I should be able to get through the week. I can also top it off using a generator that I'll have running to provide tunes during happy hour.

I secured the water loop to the top of the duracool with zip ties. I also used zip ties to connect the ends of the duracool. I decided to run one layer of duracool first to see how it would perform. This only got me about a 23 degree drop. The weight of the water on the pad caused the pad to sag a bit and I figured that air was short circuiting the pad because it wasn't pressed up against the bottom of the lid. I ziptied the pad and cooling loop to the bottom of the lid. While I like this because it definitely creates a good seal, it didn't help get my temp down any further. I added a second layer of pad and POOF, 30 degree land!

Thanks Figgy!, this will for sure extend my tent time. Last year was my first and, no joke, I don't think I slept more than 20 hours the entire week. As Nelly would say, "It's getting hot in hurr." And I did take off all my clothes. Then I was just naked and hot still and couldn't sleep. Not this year, I'll be naked and comfortable. Well things are gonna get sweaty still but bucket cooler can't cure that! Ha, thanks again!!!!!!!
Burn Burn yes you're gonna Burn.

User avatar
FIGJAM
Posts: 10233
Joined: Thu Mar 25, 2010 10:39 am
Location: apache junction az.

Re: cooling your tent or van

Post by FIGJAM » Wed Aug 14, 2013 8:37 pm

8)
"Don't buy ur Burn...........Build ur Burn!"

"If I can't find an answer, I'll create one!!!"

Fuck Im Good Just Ask Me

Wendle
Posts: 2
Joined: Thu Aug 15, 2013 5:22 am
Burning Since: 2013
Camp Name: Steve Vamper

Re: cooling your tent or van

Post by Wendle » Thu Aug 15, 2013 5:34 am

I hot glued one of these: http://www.amazon.com/Intermatic-FF4H-4 ... B002RMZ57W to the outside so I can set it and nap worry-free that the water will not run out and burn out the water pump.

Image

User avatar
Canoe
Posts: 3739
Joined: Sun Jul 31, 2011 8:01 pm

Re: cooling your tent or van

Post by Canoe » Thu Aug 15, 2013 6:50 am

Nice!
Mine is only good for sixty minutes.
Video games are giving kids unrealistic expectations on how many swords they can carry.
.
... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

Wendle
Posts: 2
Joined: Thu Aug 15, 2013 5:22 am
Burning Since: 2013
Camp Name: Steve Vamper

Re: cooling your tent or van

Post by Wendle » Thu Aug 15, 2013 7:39 am

I also found these: http://www.amazon.com/gp/product/B0049XEDMK which I feel help to hold the cooling pad upright against the bucket and even out the airflow over the pad. The gap between the basket and the bucket is perfect to hold one layer of aspen pad against the bucket, which would probably be about the same as one blue pad, but since it kind of directs the air downward over the pad it is increasing the amount of dwell time on the pad and is probably the same effect as having the air go directly across two pads; the air is quite cold coming out.

Image

holymoley
Posts: 3
Joined: Tue Aug 06, 2013 3:37 pm
Burning Since: 2011

Re: cooling your tent or van

Post by holymoley » Thu Aug 15, 2013 8:40 am

This thread has been amazingly helpful, thank you so much you guys. We are assembling two of them, test run this weekend :)

I'm sorry if this has been brought up already; I searched the previous posts but couldn't find an answer. Is it necessary to solder the fan and pump wires together? Could you just attach both to the battery or would it not be as effective?

Thanks!

User avatar
TT120
Posts: 1760
Joined: Fri Jun 03, 2011 8:43 pm
Burning Since: 2012
Camp Name: Orphans TOO!
Location: Sacramento, CA.
Contact:

Re: cooling your tent or van

Post by TT120 » Thu Aug 15, 2013 8:58 am

I spliced longer wires to the pump and fan and then just connected them both to the battery. Works fine.

Image
Life's a bitch, then you go to Burning Man - Unjonharley
We welcome the stranger, but that doesn't mean we have to like them, nor they us, and that's alright. - AntiM

W6BJD

guerrillayogi
Posts: 35
Joined: Wed Jul 31, 2013 8:48 am
Burning Since: 2009

Re: cooling your tent or van

Post by guerrillayogi » Thu Aug 15, 2013 1:13 pm

Regarding batteries and solar:

Would it be feasible to run at least the CPU fan off a UPS-type 12V battery? such as this:


I know that it will only run for ~2 hours, so I'll need at least two of these. I can charge one using my solar panel, and operate using the other one, and rig up a switch to go back and forth. Can this work?

holymoley
Posts: 3
Joined: Tue Aug 06, 2013 3:37 pm
Burning Since: 2011

Re: cooling your tent or van

Post by holymoley » Thu Aug 15, 2013 1:23 pm

TT120 wrote:I spliced longer wires to the pump and fan and then just connected them both to the battery. Works fine.

Image
Thank you!!!!!!!!!!! Have an awesome burn :)

User avatar
Canoe
Posts: 3739
Joined: Sun Jul 31, 2011 8:01 pm

Re: cooling your tent or van

Post by Canoe » Thu Aug 15, 2013 10:05 pm

IF YOU JUST WANT TO BUILD YOURSELF A RELIABLE EFFECTIVE SWAMP-COOLER, SKIP THIS POST AND FOLLOW ONE OF FIGJAM'S DESIGNS.
It contains explanations of details you don't need to understand in order to build his designs.
Wendle wrote:I also found these: which I feel help to hold the cooling pad upright against the bucket and even out the airflow over the pad. The gap between the basket and the bucket is perfect to hold one layer of aspen pad against the bucket, which would probably be about the same as one blue pad, but since it kind of directs the air downward over the pad it is increasing the amount of dwell time on the pad and is probably the same effect as having the air go directly across two pads; the air is quite cold coming out.
Good thinking, but holding the pad against the bucket is not the way to go.
As you've described, with the pad held against the bucket and the basket held against the pad:
  • the pad intake area is reduced to the area of the holes,
  • the pad exhaust area is reduced by the the basket grid (which appears to reduce it to half in the grid area, plus what you lose for any of the solid area),
  • the airflow is not evened out as the air will take the path of least resistance, limiting travel sideways through the extra resistance of more filter media to get out through the grid's limited pad exit points,
  • the reduced effective pad intake area causes increased air velocity through the filter media, which greatly increases resistance to airflow, lowering the volume of air flowing through the cooler,
  • the higher air velocity reduces dwell time,
  • when processing hot dry playa air, you may find that the above points combine to deplete water in that greatly reduced air path, creating dry spots that will pass hot dusty air,
  • in addition to possible dry spots, the above adds up to a reduced volume of air processed for the size of the bucket cooler. Well below it's potential.
    It is very similar to using such a bucket as a water reservoir for a tiny filter pad.
Others have gone this way before, only to discover that once on playa, it does not perform well as the limitations become evident with processing hot dry playa air.

Note that aspen pads swelling with water have caused some people complications with their designs. Including swelling and filling the air gap required to maximize the bucket-cooler's potential, as described below.

Note that things touching the filter pad (like your basket) provide an alternate path for water to take, instead of flowing through the filter media, so you're also limiting the water flowing through the pad, thereby increasing the chance of getting dry spots and of limiting the evapoarative cooling. (Note that with the uni-cooler and box-cooler, where the vent-screens contact the pads, they direct any water that gets/goes on them back onto the pad.)


FIGJAM's design requires an air gap between the side of the bucket and the pad.
As the fan sucks air out of the center space of the bucket, the negative pressure created in that space will suck air out of the entire inner surface area of the pad that is above water. That in turn will suck air into the filter pad on it's other side, wherever it is above water. Due to the air gap between the bucket and the pad, this means it sucks air through the entire outside area of the pad that's above water. The air in the gap is replenished by sucking air in through the holes in the side of the bucket. (Due to the extra resistance for air flow between the bucket and the pad, there is some bias for flow through the pad closer to the hole, and there's more dust appears on the pad inline with the hole as the dust doesn't change direction as easily as the air spreading out into the air gap.) As the air flow has the largest possible surface area for entering and exiting the pad, it has the lowest possible air velocity, for the longest dwell time possible and the least resistance to air flow (greatest CFM possible), all contributing to ensure that this maximized air flow gets its maximum possible cooling. The bucket cooler uses a lot more of the pad than one would intuitively conclude based on the size and area of the holes.

(if you want to mentally reverse that, you'll see why these swamp-coolers work well when sucking air out of the bucket, but not as good when someone decides to reverse the flow and gets the fan to force air through in the other direction)
Video games are giving kids unrealistic expectations on how many swords they can carry.
.
... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

User avatar
unjonharley
Posts: 10302
Joined: Tue Sep 09, 2003 11:05 am
Burning Since: 2001
Camp Name: Elliot's naked bycycel repair
Location: Salem Or.

Re: cooling your tent or van

Post by unjonharley » Sat Aug 17, 2013 10:29 am

My Homer bucket is a little taller than Fig's.. It left a space in the top where air was coming trough.. I took another lid,cut off the outside ring and cut the center out.. It slips inside the bucket to the top of the pad... No incoming air leak..Have a spare solar pump.. Going to double the pumps. That should be enough water on the pads..

Post Reply

Return to “Keeping Cool”