DIY: Portable Cooling Unit

writ­ten 7/14/25; updat­ed 7/14/25

Back to DIY Projects Page

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 14″ 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 14″ (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 12″ 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

Back to DIY Projects Page