changes to the FIGJAM's evaporative cooler design

[eksine]

I just made the mods you guys said. i added a second layer of pading and I fixed it so there is a gap. i had to sew up the seams to made it hold together and i even sewed the tubing so it stays centered. i'm getting a about 13 Farenheit difference now. so I actually lost 10-15% efficiency over what I had before.....what..

[JayBobBoy]

Hi Figjam,

We've never met in person (I hope to solve that in a few weeks) but I've been a devoted follower of your posts and find you to be one of the most articulate and creative "playa engineers" that I have come across.

Your patience and willingness to help and share is wonderful. I've had nothing but success in following your instructions and inspirations. You've helped thousands of burners over the years.

Just in case no one has told you lately...Thanks for everything!

(I was going to post a picture of my cooler, but it's still buried at the moment)

[eksine]

Yeah thanks figjam, I forgot to say that too. I looked at your chart and my outside temp was i think 87 F and humidity was like 36%. it's the optimal condition for a evap cooler. i converted those numbers for 110 degrees F and 10% humidity like you said and I got a 25 degree difference. so if we had compared our coolers together at burning man or where ever you would have beat me by 5 degrees...but then your fan is putting out 40cfm more air than mine, it is running at .4amps less than mine and your pump is outputting double the flow...so I'm going to add 2 more fans to my design. thats a total of 3 fans, 450 cubic feet per minute and I am at 10-15% less effiecint with my new changes to the pads. actually no I'm not . I'm just going to call it quits and go watch some tv on amazon. this is too much work

[FIGJAM]

Thank you.

Just my way of gifting.

[Canoe]

First.
Good build quality. Very impressive!

Second.
As you saw with the tables FIGJAM posted, a swamp-cooler can get a better temperature drop once you're in dryer air. The relative humidity up where you are typically ranges now from 36% to 56%, so the air won't suck up as much water (won't be cooled as much) so the testing you can do at home is very limited as far as showing results before you get to the playa. So you're kinda stuck having to listen to those who have succeeded on the playa if you want to have the most success possible on-playa.

Third.
The concern is, if you don't follow the details that have been proven on-playa, will you get enough hot playa air cooled enough to be effective for your car (hot air gets enough time exposed to enough water, and have enough water available for the rate of air flow, for it to suck up enough water to get cooled enough)?

• For cooling your car, which is a small volume to cool, the details may not matter much.
  You'd find out once you're on playa in the heat (and this year isn't supposed to be crazy hot, increasing the chances you'd be o.k.). Note: if it's not working out for you on-playa, do take FIGJAM up on his offer for you to drop by and visit him.
• But for someone wanting, or needing, a bucket swamp-cooler that will provide the most cool air that such a bucket can, building it the way you initially did will not do that job.
• Same for your fan & pump choice. Could be o.k. for a small space, like your car, but not what's recommended for getting the most cool air that a bucket design can provide.

[Canoe]

FIGJAM's bucket design's pad draws air from the gap between the pad and the side of the bucket. In your initial build (no gap) with the pad tight to the side of the bucket, the pad can only draw air directly from the holes.

• Air flow is through a greatly reduced area of the pad.
• Water flow used/available is from that reduced area.
• This gives the same result as using a tiny bucket, with a tiny filter, sitting on top of a larger bucket of water, and with reduced water flow.
• With air flow through a smaller area, air moves faster through the pad; air is exposed to less pad (less water) for less time.
• Air velocity is higher, so drag is higher, so the air flow through that smaller area of pad is even less that you'd expect from just a reduced area. Your fan's actual CFM performance may be reduced (FIGJAM's fan's pressure is ~17. Yours is ~14.)
• We know that the bulk of the dust that blows in is washed off of these pads, maintaining the large surface area of water provided by the filter material of the pads.
  Pads tight to the side of the hole & bucket may retain more dust.
  With any dust that doesn't get washed off:
  - with the gapped design and its larger pad area exposed to air flow, this is known to not reduce the overall effective cooling (if there are any degraded areas, the air flows to an area with less resistance)
  - with the pad tight to the hole, the dependance on that reduced pad area may mean dust may reduce the effective air flow and/or water surface area for the latent evaporation.

As the air velocity through the pad is much less with a gapped pad installation, compared to the air drag of a single pad up against the holes, with a gap between the side of the bucket and the pad: a double pad will have minimal affect on airflow over a single pad, while providing the air with more time and exposure to water.

Put another way, the reduced air velocity and a double pad means less chance of the dry air:

• getting through without sucking up as much water as it can (not getting cooled as much as it can),
• depleting the water on the filter media so there's a dry spot for hot air to sneak through.

Note: if you use foil-sided bubble-wrap to cover your windows (and roof if the paint is dark), you'll stop your car from acting like a solar oven and it will be a lot cooler to begin with.

[Canoe]

And no to multiple fans. If you need more cooling (your car shouldn't) go with the uni-cooler as it makes more efficient use of the pad's area. (With the bucket, as more air flows through the pad closer to a hole, not evenly across the whole pad, performance is not as good as a unicooler where a much larger % of the pad has optimum air flow).

Unnecessary Power Usage - if you're trying to stretch your battery for the fan & pump.

• red indicator light uses some power, although not much,
• remote on/off switches use power all the time to power the receiver,
• watch out for the same from a digital timer – mechanical timer switches can be had that don't use any electricity to operate,
• the above won't matter if you've got solar to recharge the battery up, or at least enough of one to replace the power the above use, or if you don't care and have the means to easily recharge the battery on-playa.

> I glued plastic hooks so I could stretch rubber band to hold the pump in place.

Hope they don't come off, and hope they can't fit into or block your pump's intake.

> portable battery/air compressor ... make your own easily by buy a regular car battery and a battery box with a 12v socket added in.

• Do not use a car battery for this application, unless you don't care about the cost of replacing it. as you'll be replacing a car battery much sooner.
  And it had better not be the one you expect to start your car with to drive out of BRC.
• Use a deep-cycle battery.
• google to learn the difference between the two

> solar panel ...You can fabricate a car roof mound for the panel by using neodymium magnets or 3M VBH double sided tape

• Solar panel (think sail), magnets, plus playa winds = very bad idea.
• Winds can buffet your panel and hence scratch your paint.
• Playa winds can go over 75 mph.
• A panel that goes airborne in those kind of winds could seriously injure, or even kill someone. If that happens, someone will hunt down the owner of such a panel. They will have lots of help.

> the cooler isn't as cold as i thought so the best way with the heat is put the cooler on the passenger side floor and aim the ducting litterally inches from your face/body.

As FIGJAM said, it'll just be a humidifier, and once the air is saturated, then it's just a fan and adding the heat from the electricity powering the fan and the pump.

> I thought about the leak too and touching the pads through the holes on the outside feels really really wet too, but seriously..it doesn't leak,

You'd find out on playa. But you've got for a gapped design now anyway, so you're good for leaking out the holes and good for improved air flow with more of the filter pad put to use cooling the air.

> saving the extra layer of padding so you can ... change out your pad

With the recommended filter pad and pump, most of the dust gets washed off. No need to change it out. Don't know about your pump will provide enough flow for the volume that will get evaporated and for washing the dust off the pads. FIGJAM's does.

[Canoe]

> using a walmart bucket

Looks interesting! - with the strengthening ring higher up, it may allow for more room for holes (let more of the pad have improved air flow) while retaining the same volume of water.

I like your choice of ducting hose:

• can be gently curved (no abrupt corners), for the least drag in getting to where it needs to go,
• can expand/contract somewhat, so you can adjust your setup on playa, for installation or for optimization of flow,
• the interior surface (with no abrupt nor large ridges or gaps from joints along it's length) makes for a nice consistent boundary layer of air for the air flow to slide easily by with little drag,
• the shinny metal will reflect heat away so the cooled air isn't absorbing as much heat from the hose as darker materials (absorbs heat from the air, radiated from air & ground, and worse if directly in the sun), and
  reasonably robust in the wind, if secured adequately.

[atomicray]

Been a while since I have had a chance to swing by...traveling a fair amount over the year between Texas and Belize...but I get here today and find an interesting thread.

I was intrigued by the title...having been on board the Figjam process since the beginning I was interested to say the least...the quality of the workmanship and the photos, top notch...the function, the issues have been noted already.

But I would offer one word...humility.

BM is all about being yourself and many burners have the FU, FtW, and Raaaarrrr attitude...but I don't. I appreciate the effort, the consideration, application, and attention to the topic that Figjam has provided.

I would offer that you make one exactly as noted and designed by Figjam, then compare this one to the function of yours.

Best of luck and success with your project and your burn

[DustyFrank]

I just got off the phone with Jameco tech support.

The Jameco fan you suggest, which has 4 wires and is specified as DC on their page, will not run on plain old Direct Current. This is unfortunate because it has a nice high CFM output.

It requires a pulse width modulated speed controller, which Jameco does not sell.

I think you might be able to get one at Amazon, and have ordered one to test with the fans that I ordered and received from Jameco.

[DustyFrank]

So I took the fans apart and figured out from the diagrams, spec sheets etc. which wires were actually + and -.

Result: the fans work as they should, and have plenty of power.

For those who might want to control the fan speed, Amazon sells a 10 amp pwm controller, which I also tested, and it works fine. (http://www.amazon.com/Controller-Knob-H ... B007TH4EN6)

I just got off the phone with Jameco tech support.

The Jameco fan you suggest, which has 4 wires and is specified as DC on their page, will not run on plain old Direct Current. This is unfortunate because it has a nice high CFM output.

It requires a pulse width modulated speed controller, which Jameco does not sell.

I think you might be able to get one at Amazon, and have ordered one to test with the fans that I ordered and received from Jameco.

[DustyFrank]

Delta 152 cfm 12v fan with pwm controller.JPG

Shown are the Delta 152 cfm fan from Jameco, along with the pwm controller I discussed above.

Looking at the fan on the black label side, the wires exiting from the motor, counter clockwise, are positive, negative and unused. Don't bother trying to decipher the wires from the spec sheet, you need to expose and separate them as shown to know which is which, as they are not generally mounted to the fan in the sequence shown in the spec sheets.

The speed controller has 4 terminals. From left to right, they are:

1. Motor negative
2. Motor positive
3. Power negative
4. Power positive

Note: You can control two of these fans with one controller.

[jasonryan]

Nice! So it looks like you can use that "PWM" controller from amazon even if your fan doesn't have a PWM output--you just need the negative and positive from the fan, right? So we can use that controller to control any fan and turn down the speed if we so desire (ie. the bucket cooler is making things too cold)?

Good work.