My goal is to optimize the design of a portable swamp cooler to my camping setup, for portability, cost, and efficiency.
Burning Man has been an accelerated testing ground for technology for
a while. Even the military are rumored to send observers. (They
supposedly discovered the Camelbak there.) Up to 50k+ imaginative
burners come back every year fine tuning their designs for comfortable
desert living. Swamp coolers is one great example of crowd sourced,
internet accelerated engineering. Each year, the latest design tweaks
show up, results are observed by their builders and others. Then the
results are shared and discussed online, new tweaks are invented and the
cycle repeats.
I'm starting with a fairly well tested design that's been used for
several years, Figjam's 12 volt system, recapped on page 51 of the
eplaya forum: https://eplaya.burningman.com/viewtopic.php?f=280&t=33842&sid=64402fca15c15b9e43b9eec3b88fceeb&start=1500
I'm adapting this design to my situation, which is a bit different.
- Instead of a full size cabin tent or hexayurt(700+ sq ft), I have
been using a tent within a tent for several years, basically a large
piece of housewrap suspended from the cabin tent, draped over an air
mattress and tucked under at the edges. It has overlapping flaps on the
sides for entry, or can be pulled completely out of the way to allow
cross ventilation. It has an interior bamboo spreader pole over the head
end, and I'm generously calling it an average height of 2 ft. (about 75
cu ft max, probably more like half of that). Figjam calls for a fan
that will replace the air inside the space every 3 to 5 minutes. For my
tent, that would be no more than 10 to 30 cfm. (He uses a 190CFM muffin
fan) I'm happy to overkill design and loosen the fan to lower air output
if needed.
My main question is fine tuning the efficiency. Typically this design
is reported to give a 20 to 30 degree decrease over ambient incoming
temp. I'd like to maximize that. My cooled space is very small, so a
large volume of air is not needed, as in larger spaces. I'm thinking
that the slower the air passes through the wet media, the more it is
humidified and cooled. Too fast, not cool enough, and it passes through
the tent too fast. Too slow, and not enough air passes through.
- I have access to 110VAC power in my camp, so am using AC
components. My pump is a 132gph fountain pump. I'm putting a TEE and a
valve at the outlet so I can dump extra flow. The drip ring only needs
enough to keep the entire mat damp. I'll be carrying 12 volt backup pump
and blower with a DC adapter also. The playa eats technology,
redundancy is essential! This will also make it easier to convert to DC
someday if I want to.
- I plan to have a float switch to prevent dry running in a second
bucket reservoir and a siphon loop connecting them. This should give me
twice the water capacity. (If I can remember to check the water daily, I
might be able to forgo the switch.)
- My system will have a thermostat to narrow the range. No sense in
overcooling. I have an old ductstat that should work. I have a digital
Ranco controller I use for homebrewing, but that would be overkill.
- I travel from Florida so weight of cargo is critical. We now have a
rental storage unit so can leave stuff out there, but there is no way
we can store batteries effectively.
(Greywater disposal technology is another good example of this design process, but that's another story.)
3
Portable Swamp Cooler 
Re: Portable Swamp Cooler
Comments rated to be Good Answers:
Comments rated to be "almost" Good Answers: