How to Build a Swamp Cooler (Steve Guilliams Design)
All design and engineering credit belongs to the brilliant Steve Guilliams. Steve’s design is adapted from this original, smaller design by FIGJAM. In Steve’s words: “What FIGJAM says is the word of God.”
It’s a sweltering afternoon on the playa. Just thinking about leaving camp to bike around and bake in the hot sun is making you tired. But it’s too hot to sleep. Fortunately, you were radically self-reliant and built a swamp cooler. You step into your playa home, turn on your homemade air conditioner, and find sweet relief. While most people are roasting in the 100 degree heat, your dwelling registers at a comfortable 70 degrees. It’s cool enough to invite your friends over for a yoga class without breaking a sweat.
The basic principle at work with sweat and with a swamp cooler is the same: evaporative cooling. As your sweat evaporates, it cools down your skin and core body temperature. With a swamp cooler, simply pumping water and allowing it to evaporate efficiently lowers the temperature of the air. The playa is very dry, making it the perfect environment to use evaporative cooling.
You will want to make sure your battery is connected to the fan and pump after setup on-playa, and possibly house the battery in another plastic bin for protection against rain. You will also want access to a few liters of water a day to refill the swamp cooler, and a battery charger to recharge with the help of a generator.
Find some playa buddies and whistle while you work!
SUPPLIES
A rectangular plastic bin, ideally with sides that are as vertical as possible. This is your swamp cooler housing. It should be at least 18 inches tall to allow for 12 inches for the fan and 6 inches for a water reservoir below. This set of 4 was at Walmart for $56.
A deep cycle marine battery, like a car battery, but for boats. You want a big battery for increased energy capacity — a car battery will work just fine but you might last the entire week on the playa with this beauty. $85 at Walmart.
The Endless Breeze 12V fan, providing very efficient airflow for the power it draws. On sale now for $64.
This submersible water pump, available for $12.
Clear plastic tubing. This one has an internal diameter size which fits well over the output of the aforementioned pump.
Ring or U-shaped water dispenser at the top with holes in it. You could get a T and make this out of more plastic tubing, which would look like this. We got a U-shaped piece of PVC pipe and glued it to the plastic tubing with industrial adhesive.
Blue cooler pad material like this which will be super-evaporative.
Metal wire.
Low-density foam tape. We bought this 3/8in-thick tape.
A little bit of electrical tape.
TOOLS
Power drill & drill bits
X-acto knife
Soldering iron
BUILD
- Unscrew the fan’s housing and remove the front face of the fan.
2. Drill 4 holes in the shape of a large square into the fan’s front face. Use the same measurements to drill similar holes in the big plastic bin. Later you will screw the fan and bin together through these holes.
3. Measure the circle where the fan actually blows air. Using a Sharpie and X-acto knife, cut a circular hole in the big plastic bin to these dimensions.
4. Cut the appropriate length of PVC pipe so it’ll form a U-shape in the housing if you look from the top. This U-shape should be supported vertically by more PVC pipe and pipe feet. The vertical parts are just for structural support to hold up the U, no water will flow through them.
5. Piece-by-piece, disassemble the PVC structure and use a Sharpie to mark off holes on the underside of the U-shaped PVC. The holes should be about 1" apart. Drill the holes as marked. This is where water will drip out of the PVC structure and onto the evaporative foam.
6. Cut the blue evaporative foam into a size that’ll fit around the U-shaped PVC pipe.
7. Cut the wire into about 4" length strips. Then, at a spacing of about 3" apart, jab them through the blue foam and secure the foam to the PVC structure like you would with twist-ties. Try to tie things so the blue foam is vertical and flat like walls, and thus will align better with the holes where water will drip. Do not block any of the holes for water dripping with your metal twist ties. Make sure the corners have good support through the PVC feet and twist-ties.
8. Screw the fan to the inside of the plastic housing, making sure that the air will blow outward. You may want to cut a hole for the switch first, or do that later.
9. Connect one end of the clear plastic tubing into the ring or T-shaped water dispenser. Connect the other end to the water pump.
10. Solder the switch terminals to both the fan and pump, so the positive (+) position on the switch matches positive on the fan & pump, and likewise for negative (-). Then drill holes into the plastic housing and screw in the switch.
11. Mark the positive (+) and negative (-) wires coming out (the fan had the longest and most robust cables so we used that) and leave them pretty long so they can connect out of the big plastic bin and eventually to the battery.
12. Close the plastic bin lid and see if there are any small gaps in height between the PVC pipe and lid at all. If so, apply foam tape and make sure the fit between the plastic bin’s lid and the PVC pipe structure is as snug as possible. The air inside the U-shape is going to be cool after evaporation via the blue mat, so you don’t want that nice cool air leaking out from the top of the plastic bin instead of going into your yurt. You might also want to use foam tape to seal the edges where the plastic bin fits its lid — we did just to minimize gaps (scroll to see pic in step 14).
13. Using an X-acto knife, cut large panels out of the plastic housing that will let hot air in. Take care not to cut too low, because the bottom of the housing will be filled with a few liters of water and you don’t want water to slop out. I decorated with some duct tape.
14. Ready to transport to the playa! Don’t forget your battery. We brought an extra plastic bin to house the battery, just in case it rained. We also brought a vent (the silver thing) for the top of the yurt, to provide extra air flow. We ended up not installing the vent since things worked well without and we were too lazy to cut an extra hole in the yurt.
15. Put the battery in the extra plastic bin, connect the wires to the swamp cooler, and stack the swamp cooler housing on top. Use the height of this battery-and-swamp cooler stack to position the hole that gets cut in the next step. You don’t need to stack, it’s just what we ended up doing.
16. Carefully cut a hole in the yurt and tape around the hole with yurt tape, aka 3M wide bidirectional filament tape. Then tape the fan-to-yurt gap. There may be ways of getting around cutting a hole in your playa housing, but the key thing is that you need the swamp cooler to directly interface between inside and outside air. If you just put the entire swamp cooler inside, it will merely circulate slightly colder air, but will not bring in cold air while letting hot air escape through the vent, providing true air flow. You will get nowhere near 30 degrees of cooling if you do not allow the air to circulate between outside & inside.
16. Once your battery is charged and you connect it to the swamp cooler, pour water into the bottom of the bin, flip the switch to turn on the fan and water pump, and the cooler will start working! Depending on how much you use the cooler, you will want to pour more water into the bottom of the plastic bin every day or two. You’re all done! Congrats and enjoy your newly cool home on the playa.
