cooling your tent or van

[FIGJAM]

Mine had the pump amps added to those base figures.

[kman]

Mine had the pump amps added to those base figures.

That's actually quite good news, if I end up getting the solar fountain pump to use with the bucket cooler.

[rodiponer]

Figjam, I think the ultimate in swamp cooler nerdiness is a two stage heat exchanger. Instead of cracking a window to let air escape, you let the cold inside air escape through a heat exchanger that cools the incoming hot air before it hits the evaporative pads and cools further. This increases efficiency of the system and decreases the humidity.

A random Google hit on the process:
http://www.toolbase.org/Technology-Inve ... ive-cooler

I also read that thicker pads increase the efficiency and amount of cooling. There are high efficiency thick pads for normal swamp coolers, and one of the commercial 12 volt swamp cooler manufactures found that they make the output air much cooler.

But I think your system is already high tech enough. Honestly, it's not THAT hot .

[FIGJAM]

You can double or triple layer the pad, mastercool has one 8in. thick pad, but thier only open on one side. that replacement pad is expensive. Ive never used more than 1 layer in 50 years. If I understand the physics
correctly, coolers can only reduce temp in the 30 degree range under optimum conditions, but thats based on experience, not knowlage of the science.

[FIGJAM]

http://www.homedepot.com/h_d1/N-5yc1vZ1xg6/Ntk-All/Ntt-cooler%2Bpads/h_d2/Navigation?No=12&langId=-1&storeId=10051&Ntx=mode+matchpartialmax&catalogId=10053

Its not shown here, but the blue pad also comes in like 10ft. rolls if you want to try multi-layers.

[FIGJAM]

I used plumers goop to glue my box together, then siliconed the inside seams. You can build the box out of wood, but buy a good marine paint for the inside and out. I like the idea of plastic or fiberglass cause its lighter.

[victorian rocketship]

Where do you get the fan from?

[FIGJAM]

Graingers, but look at used computer fans with the same specs (107cfm 3000rpm .52amps) they will be cheaper.

[ConnieH]

I'm going to build Figjam's bucket model cooler and have everything I need except for the fan. For the top vent piece, I found an HVAC part in the shed that looks very similar to this:

http://www.hardwareandtools.com/Gray-Me ... 33477.html

I was planning on using a computer fan on top of the bucket (possibly salvaged from my old computer that just died on me), blowing into the round end of the vent above, and am considering getting one of these to mount on the inside top of the vent to pull more air through the elbow and out the rectangular "register" end:

http://www.amazon.com/gp/product/images ... lectronics


What do you all think? Worthwhile or excessive? I think it was in this thread someone talked about the reduced outflow of air due to the elbow, and I thought maybe this would keep it moving?[/img]

[kman]

I suspect you'd do better just mounting another 120mm fan on the inside. Case fans like that tend to be (a) small or (b) loud... you don't often get both in one.

Also, mind your voltages... that may or may not be drawing off a 12v rail. Be sure you have the right power supplied to the fan.

Looking at the specs for your blower, though:

22 CFM
Noise 28 dB(A)

I'd get a simple case fan instead:

https://www.amazon.com/Cooler-Master-120mm-Case-R4-C2R-20AC-GP/dp/B0026ZPFDE/ref=pd_cp_e_1
Up to 90 CFM
Noise 19 dB-A

Tons more airflow and a lot less noise.

[kman]

The dayton is 4in. 3000rpm and 107cfm. $32.

Is this the fan you bought?

http://www.grainger.com/Grainger/items/4WT36?Pid=search

[FIGJAM]

Connie... the reduction in air flow caused by the 90 is minimal. The second fan is a power drain that you dont need and if it doesnt push more cfm the the first fan its just blocking your flow. How big the space is very important. the cooler should completely replace the air inside every 3 to 5 minutes for the best results.

[FIGJAM]

Kman...I think thats the fan. If it was turned around, I could tell for sure, but the specs look right.

[nolaTee]

If I build the first model in the five gallon bucket will that be good enough for a tent that is 12'x7' and placed under a monkey hut? Also should I place the bucket under the hut or in the sun? Will it work if I put my vent throught the small zipper at the bottom of the tent and therefor lower than the top of the bucket?

Also if I use a solar powered pump, what is my best option for powering the fan? a car battery? Ive seen this done at other festivals but have never done it myself. (also a virgin burner) Will it just last awhile or will I have to charge it up?

I know thats a lot but any info helps, Thanks!!!

[FIGJAM]

Because the tent is shaded it will help alot. The cooler being in the shade wont matter cause the air is just as dry and hot, which is what makes it work so well. Only vent as much air going out as is coming in from the cooler and it wont matter were the cool air comes in to the tent. If your tent is 6ft tall, the total space inside is 504 cubic feet. That means the air inside will be replaced every 5 minutes. I dont know what kind of car battery you have. Thier different than deep cycle which are rated in amp hours. Say if you have a 50ah battery, and the fan uses .5 amps, then you can run the fan for 50 hours before the battery is half way discharged (which is what is recomended to preserve battery life). Car batteries not ment to be used this way, but if you used the cooler for 4 hours a day and just started your car for an hour every other day, it should be fine. But Im just guessing on that last part. Hope this helps.

[ConnieH]

Connie... the reduction in air flow caused by the 90 is minimal. The second fan is a power drain that you dont need and if it doesnt push more cfm the the first fan its just blocking your flow. you can get the 4" vent hose that you can see in the playapod pics and use clear 100% silicone to attach it to the fan.Then put a more gradual bend into your structure useing just the hose. Keep it simple and I think you will be happier. How big the space is very important. the cooler should completely replace the air inside every 5 to 10 minutes for the best results.

Thanks Figjam (and kman!), I'll just stick with one fan on the cooler, and maybe add a fan on the opposing wall of my hexayurt to blow air to the outside, maybe creating a cross-breeze of the cool incoming air?? By my calculations, the yurt is 885 cubic feet, so a fan with 107cfm would replace the air every 8.27 minutes - is that correct? And I've been reading that fans with sleeve bearings shouldn't be mounted horizontally - does it make a difference in cooling if the fan is mounted horizontally on top of the bucket, or vertically inside the elbow? I'm looking for a ball-bearing fan, but there seem to be more sleeve bearing ones with the cfm I need (that I've found anyway).

I put together my bucket cooler last night in less than an hour (sans fan of course) - can't wait to test it for real now that our temps are getting into the 90's here. All the info in this thread is so amazing, I can' believe how easy this was to build - Figjam, please come by Farmopolis at 4:30 and Cairo and I'll personally make you a drink or two or three as thanks

[kman]

Side topic, I know, but what size yurt is it that you determined to be 885 cu ft? I'm making the 6' high version (extra 2' sections on the bottom) and haven't gotten around to figuring out the internal area yet.

*shudders at the thought of dusting off those rusty math skills*

[ConnieH]

Side topic, I know, but what size yurt is it that you determined to be 885 cu ft? I'm making the 6' high version (extra 2' sections on the bottom) and haven't gotten around to figuring out the internal area yet.

*shudders at the thought of dusting off those rusty math skills*

Mine is the "regular" hexayurt with 4 foot high sides...I hope I did the calculation right for cubic feet (my math skills are very rusty!)...floor area is 166 sqft x 4 ft = 664 for the bottom 4 feet; 1/3 x 166 (floor of "top cone") x 4 ft = 221.33; 664 + 221.33 = 885.33 cubic feet.

If my formula is correct, your top cone would be the same, and adding the additional 2 feet would increase the bottom 6 feet to 996 cf - right?

[kman]

Side topic, I know, but what size yurt is it that you determined to be 885 cu ft? I'm making the 6' high version (extra 2' sections on the bottom) and haven't gotten around to figuring out the internal area yet.

*shudders at the thought of dusting off those rusty math skills*

Mine is the "regular" hexayurt with 4 foot high sides...I hope I did the calculation right for cubic feet (my math skills are very rusty!)...floor area is 166 sqft x 4 ft = 664 for the bottom 4 feet; 1/3 x 166 (floor of "top cone") x 4 ft = 221.33; 664 + 221.33 = 885.33 cubic feet.

If my formula is correct, your top cone would be the same, and adding the additional 2 feet would increase the bottom 6 feet to 996 cf - right?

Let's go with "right!"

(assuming your initial maths of 166 sqft are correct, at least, I was hoping someone would do the work. thanks! LOL)

Close enough for a general idea, certainly, which is all I really need. I figure if I go with the nice quiet 90 cfm fan I linked earlier, that puts me close enough to the 10 minute mark that I'm comfortable.

Groovy!

[FIGJAM]

Connie... the reduction in air flow caused by the 90 is minimal. The second fan is a power drain that you dont need and if it doesnt push more cfm the the first fan its just blocking your flow. you can get the 4" vent hose that you can see in the playapod pics and use clear 100% silicone to attach it to the fan.Then put a more gradual bend into your structure useing just the hose. Keep it simple and I think you will be happier. How big the space is very important. the cooler should completely replace the air inside every 5 to 10 minutes for the best results.

Thanks Figjam (and kman!), I'll just stick with one fan on the cooler, and maybe add a fan on the opposing wall of my hexayurt to blow air to the outside, maybe creating a cross-breeze of the cool incoming air?? By my calculations, the yurt is 885 cubic feet, so a fan with 107cfm would replace the air every 8.27 minutes - is that correct? And I've been reading that fans with sleeve bearings shouldn't be mounted horizontally - does it make a difference in cooling if the fan is mounted horizontally on top of the bucket, or vertically inside the elbow? I'm looking for a ball-bearing fan, but there seem to be more sleeve bearing ones with the cfm I need (that I've found anyway).

I put together my bucket cooler last night in less than an hour (sans fan of course) - can't wait to test it for real now that our temps are getting into the 90's here. All the info in this thread is so amazing, I can' believe how easy this was to build - Figjam, please come by Farmopolis at 4:30 and Cairo and I'll personally make you a drink or two or three as thanks

Thats the info I wanted.
Because your yurt is made out of insulated material, the cool air wont dissapate very quickly. Im not worried about the fan being horizontal or vertical since thier made for continuios use, I dont think a few hours a day will effect endurance.
I still think it will work fine without the exit fan. Houses here dont use them and a tiny bit of positive pressure will help keep some dust out.
But bring the extra fan as a spare or use it to curculate air inside the yurt.

While your waiting for your fan, test the pump with the lid on the bucket and in an hour feel how cool the water gets. I think you will be suprised.
Whats the average humidity during the day there?
Testing the pump will let you practice dealing with small leaks by just pushing the clothe in a little at that point with your finger, when you release the leak should stop. You could also get one of those shallow plastic catch pans for a 5gal. plant pot to set the cooler in for piece of mind, but I really didnt have an issue with leaks.
Id love to see a picture of your bucket to makesure you got enough holes. If you look at the first pic of this thread, then go to the pic with the cooler hooked up to the playapod you will notice that I added more holes. This is because when I first drilled the holes, I was conserned about the integrity of the bucket, but it turned out to not be an issue.......AND I will see you on the playa.

[ConnieH]

We have low humidity here - it's about 17% today and going to be 97 degrees by Saturday, so perfect test weather! I have a small fan we took out of the bathroom recently that I'll use to test with while waiting for a new one...I'm still wrestling with the idea of building a solar fan similar to an attic fan that will only come on with the sun, just like the pump. If I connect a 12v fan to a solar panel with sufficient wattage (probably 10W+?), it should work, right? I see Harbor Freight has their 45watt solar system on sale for $159...I've had my eye on that for a while, maybe they still have some left at the store

My man painted the bucket today, I'll snap a picture tonight and post tomorrow!

[FIGJAM]

Im a little concerned about solar. My reseach is showing that the rated watts is what the panel will produce in an entire day, not constant output. Maybe I missunderstood. Maybe someone can clearify this.

17% there, 6 to 9% here could mean a difference of maybe 10 degrees in temp from the cooler. On the playa its more like here so the cooler will be more effective.

[kman]

Im a little concerned about solar. My reseach is showing that the rated watts is what the panel will produce in an entire day, not constant output. Maybe I missunderstood. Maybe someone can clearify this.

17% there, 6 to 9% here could mean a difference of maybe 10 degrees in temp from the cooler. On the playa its more like here so the cooler will be more effective.

Tell you what, I'll see if I can connect some stuff to my 5w panel and I'll let you know for sure.

[rodiponer]

Im a little concerned about solar. My reseach is showing that the rated watts is what the panel will produce in an entire day, not constant output. Maybe I missunderstood. Maybe someone can clearify this.

That isn't right. At sunny Burning Man my 135 watt panels output about half of their rated output every hour for most of the day-- about 70 watts, or 6 amps each. For the hour around sunrise and sunset they only produce one or two amps.

My very unscientific rule of thumb is that you can divide the wattage by 3 or 4 to get the number of amps per day the panels will charge the batteries.

There are other factors. Batteries that are discharged down to about 50% or capacity, and lower, will not be charged efficiently by a PWM or shunt solar controller. The solar panels have a natural voltage that is too high for batteries in this state. Only an MPPT solar controller will be able to dump most of the solar panels output into batteries in this state, though, of course, an MPPT controller from a US source costs as much as a second solar panel that will add more overall output.

Batteries that are nearly full cannot absorb electricity quickly. So getting that last 10-15% of charge can take a long time. AGM batteries are slightly better at this than sealed or wet cells.

So it's best to either have a larger battery bank and/or AGM batteries and/or an MPPT controller. Or more panels. Or less consumption. ... and etc.

[PugRay]

Im a little concerned about solar. My reseach is showing that the rated watts is what the panel will produce in an entire day, not constant output. Maybe I missunderstood. Maybe someone can clearify this.

That isn't right. At sunny Burning Man my 135 watt panels output about half of their rated output every hour for most of the day-- about 70 watts, or 6 amps each. For the hour around sunrise and sunset they only produce one or two amps.

I'm wondering what a light meter would reveal in terms of exposure versus panel placement. what If the panel(s) were fixed to an adjustable mobile base or stand like the wireframe mock-up in the diagram.

the stabilizer ring at the bottom could be moved up or down increasing / decreasing the exposure angle, and the base could be turned to maximize exposure throughout the day.

[FIGJAM]

[ConnieH]

Tell you what, I'll see if I can connect some stuff to my 5w panel and I'll let you know for sure.

I'd love to know if something works...the only solar panels I have are the yard light kind and those don't have enough juice to do much. I know fans probably have a bigger draw than my water pump, but the pump is attached directly to the solar panel with no battery, so in my head I should be able to do the same thing with a fan - finding the right wattage I guess would be key. We can do batteries and charge them on the camp genny, but having a cooler system that turns on and off automatically with the sun would be AWEsome!

And here is my bucket, I think we got enough holes?:

http://www.facebook.com/photo.php?pid=4 ... =640076607

[FIGJAM]

[kman]

Tell you what, I'll see if I can connect some stuff to my 5w panel and I'll let you know for sure.

I'd love to know if something works...the only solar panels I have are the yard light kind and those don't have enough juice to do much. I know fans probably have a bigger draw than my water pump, but the pump is attached directly to the solar panel with no battery, so in my head I should be able to do the same thing with a fan - finding the right wattage I guess would be key. We can do batteries and charge them on the camp genny, but having a cooler system that turns on and off automatically with the sun would be AWEsome!

And here is my bucket, I think we got enough holes?:

http://www.facebook.com/photo.php?pid=4 ... =640076607

You can definitely do it, that's how solar attic fans work. No intermediate batteries needed. The question is what size panel is needed.

Batteries work with solar arrays [mostly] for two reasons:

1) power storage for cloudy days (or night), and
2) smoothing out voltage as panel output fluctuates.

The first isn't really a concern here, since we're only running the coolers during the heat of the day, and available sunlight during the day is not likely to be a concern on the playa (except perhaps during an especially intense dust storm), so the only question is the latter. I believe most DC fans will run on anything you feed them. Too much, of course, and you'll fry the fan, too little and it won't spin. I don't think it will harm it, however. Plenty of videos on youtube, however, showing people connecting solar arrays directly to 12v DC fans. Bigger arrays make the fan spin faster, smaller ones make it spin slower.

What pump did you use? Did you use the harbor freight solar powered pump? No worries about that one, since it's obviously made just for that purpose, and should do exactly what you want... run when there's light, stop when there's not.

I've definitely toyed with the idea of a small panel just for the swamp cooler fan. Match the right panel to the right fan, add the solar pump, and the only thing you have to do is keep water in it, and switch it off when you DON'T want it running during the day! I had been trying to figure out how to run the bigger endless breeze fan directly, but now I'm more thinking of using that as a regular fan inside, off my battery and big panels, and just pick up a small 5-10w panel just to push the cooler fan. 10w panels are available on eBay for $10-30, no problem. My only concern is damaging the fan if the voltage gets a little too high, not sure what to do about that... or if it's even a real concern. The computer fans aren't expensive, though. I have a little 5w panel that I might just use to try pushing one directly, and if it fries, not a big loss, chalk it up to learning, and if not, done!

[FIGJAM]