DIY: Portable Cooling Unit

written 7/14/25; updated 7/14/25

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What

Make your own air conditioner that’s not really air conditioning. This device made from household items helps blow cold air from water chilled by ice. It is highly customizable. Best for small spaces.

Why

The use case for this assembly can be varied. Examples: the top of my townhouse that never gets A/C properly, picnics, tailgating, my workplace whenever it loses A/C (at least once a year), etc.

Time and Effort

Time: 2-3 hours

Effort: Easy-Moderate

Materials and Cost

Materials

Submersible Pump USB, 3W/50gph

Arctic Zone Titan Cooler, 16-can

Radiator w/ Fan, 120mm/DC12V/12pipe

Tubing, 3/8″-1/2″ (0.3″-05″; 8-12mm)

Dual 3 or 4-pin USB Adapter, 12V

4in Dust Hose, sculptable/flexible

4in Bell Nozzle Dust Collection Fitting

USB Hub with Power Switches, 2.5A/5V

Cost

$6.99

$27.99 (sale)

$20.99

Free (~$6)

$8.99

$15.45

$19.98

$19.99

TOTAL: $120.39 ($126.39)

Owned Supplies

Sharpie

Dremel w/Cutting Bit

Driver w/Drill Bit

Screws, Nuts, Washers

Utility Knife

Ruler/Square

Safety Glasses

Optionalthe assembly is highly customizable

  • 120mm Slim Case Fan attached to other side of radiator for push/pull method (~$10)
  • Replace the 120mm Radiator w/Fan with a 240mm Radiator w/Fan ($36.99), Slim Case Fan 3-pack w/PWM sharing ($28.99)
  • Add another Fan to the end of the Flex Hose for even more pulling power (~$10-$30), by utilizing a 3D printer or buying a Duct Collector Flange (~$10)
  • If you don’t need the on/off switches for power, then just a dual port USB A power block is fine (~$10)
  • You can also get a USB splitter plus an in-line USB with on/off switch all connected to a 1-port wall block, but that would mean many adapters and could compromise power delivery if not careful
  • Use an insulating tape around the base of the Bell Attachment

Schematics

This is the original schematic I drew. It has different components I didn’t end up using like wing nuts, a diverter tray at the bottom, and an added plastic sheet/bracket for fastening the hose flange on top to.

Process

Planning and Measurements

  • After gathering supplies, try them out to see if they will fit, the best orientation, etc. Adjust as necessary
  • Cut Hoses to fit the Submersible Pump and Radiator w/Fan into reservoir (orange liner bucket)
  • Decide if you want to use the push or pull method (or both) for the radiator, and swap the fan to the desired side

Note: Cooler fans always have a direction of flow and spin indicator somewhere on there

  • Take measurements and mark them with the Sharpie
Notches for cords

Cutting

  • As nerve-wracking as it can be, you just gotta do it to get it done
  • Start with the notches in the plastic. I used a Dremel with a cutting wheel and it was quite simple. *Don’t forget safety glasses when cutting plastic!!*
Dremels make the plastic melt while cutting
It’s useful for keeping things mostly smooth
  • Now for the cooler. I decided to trace the inside of the Bell Nozzle Attachment to open up as much space as possible for the air movement (planning on later using a 240mm instead of just the 120mm). Using the utility knife, I cut through the 3 layers of insulating material
  • Initially, I’d planned on just setting the Bell Attachment on top of the cooler, so next, I drilled holes for the 4 attachment points through insulating material and the orange plastic (needed to stand on a stool to do this on the workbench) using a 1/4″ bit
  • Then, I traced the opening on the plastic with a Sharpie because now I can see the line through the backside. It’s time to cut the opening! Here, you have options. I think the easiest method is to run the utility knife multiple times around the shape, cutting deeper each time, then clean up with the Dremel (sanding bit) afterwards (unless you have other fun tools in your arsenal). Instead, I decided to get fancy and use aviator snips (tin snips) because they pretty much cut everything. The problem is that you have to know how to use them otherwise you mess up like I did. Thankfully, it wasn’t a huge deal. It really doesn’t have to be gorgeous, either.
Right side snips. Not sure where my left one is…
Oops. Tried to the the center snips

Securement

  • Here, you have to decide how you want to mount the Bell Attachment: Under the insulation? Above? And, even, if you want to secure it on top of the cooler fabric, or underneath it, just on the orange plastic.
Under?
Above?
  • I happen to have a huge box of loose screws organized by size, and some random washers and nuts, so I chose some 1/4″ (M6) screws
  • Initially, I used the 1″ screws, washers, and nuts to go all the way through.
  • In the end, I changed my mind used the 1/2″ length screws and attached it all underneath the cooler fabric because the 1″ screws were too long even through the fabric and would impede the fan/radiator placement inside

Final Assembly and Testing

Time to put it all together!

  • First up, replace the orange liner bucket, suction the Submersible Pump to the bottom, and replace the tray with the Pump’s cord through the notch
  • Fit the water tubes down into the reservoir through the tray’s convenient holes (bonus, this stabilizes the radiator/fan unit) and attach to the Pump
  • Attach all Power Cords and Adapters together
  • Attach the Flexible Hose to the Bell Attachment

Time to Test!

  • Move the tray aside a little, and fill ‘er up with water (make sure it’s always past the top of the Pump… You should never run those dry!) and ice packs. I happened to use ice because I ran out of ice packs testing out the first iteration of this assembly (see end of post if interested)
  • Plug it all in
Filling up!
Water is draining into the reservoir just like it’s supposed to!
  • DONE! Give it some time to start cooling
Hello!!

Result

07/14/25: The power really isn’t as strong as I’d like it to be. Ended up trying all kinds of fans (happened to have) to try and boost power. More money equals more power, but also more noise… With that said, having this when it’s about 100F with no other air source, would be a Godsend.

The cooler is insanely portable, and everything about this cooler by Arctic Zone is perfect for this application from the tray with convenient holes to the zipper-less closure, to the plastic liner tray which makes it fully waterproof, to just how nice it looks. It even comes in a 48-Can size!! Technically, you can just scoot the tray aside and carry drinks in the reservoir, too. Even food if you have space in the tray. I’m sure you can 3D print any manner of dividers if you’re not using the whole tray for fans. The largest sized cooler could really have dual fan and vent setup.

Just store the cords and block in the pockets when not using
Lift out and pour water. Easy peasey.

Here is a hose-end fan attached with a 3D printed 4″ adapter

When I have more monies, I will try the 240mm Radiator with push and pull fans, then update here.

Notes

  • Your choice on how you want to orient the fan on the radiator. You can unscrew and re-screw to the other side, or even add another fan for a push/pull method instead of just push or pull
  • Many soft-sided coolers are NOT actually waterproof! Be careful!
  • Submersible pumps are easily clogged. You do not need a powerful one. A weaker one will do just fine
  • Ice packs are preferable to actual ice, though you can use ice itself, too. The reason being tiny ice pieces can enter the pump and potentially damage the entire system
  • Very large chunks of ice do not melt easily or quickly, and can provide longer cooling than small pieces
  • This can also be done in a hardcase cooler. I chose this cooler because drilling through plastic of a hard cooler would likely necessitate some sort of sealing to retain the insulating abilities of the cooler. Like, spray foam or insulating tape?

Test Run

If you’re interested, I initially tested it all out on a small cooler/lunch bag that was free. I’d drawn schematics for 2 different setups including the smaller setup. The result was less than ideal:

  • The fan and radiator were much too large for the front pocket that I’d planned on trying
  • Poking holes through the bag to the reservoir of water is not idea for leakage reasons, yet running the hoses around the outside alongside the power cords made for a very ugly setup and high chance for leaking, not to mention reduced water-cooling capabilities
    • The cooler/lunch box ended up leaking because it’s not actually waterproof

Here are some pictures!

Original Schematic
Just need a utility knife to score and break
Mounted!
Pump goes in, but has no hard surface to suction to
Too tight a fit, so the hoses have to stick up and out
Closing it inside the pocket kinks the hoses
Pump and radiator work well!
For reference, the counter outside it was 69F
In the end it leaked everywhere and was a bust

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