DIY "Two Stage" Indirect Evap Air Cooler! No Venting and No Humidity! Two-Stage Indirect Evaporative Air Coolers are considered 'The Best of the Best'. They generate both cold-air and cold-water and both are used to maximize the efficiency of the unit (nothing is wasted). additionally, they cool the indoor air without adding any humidity to it! the biggest benefit of the 2nd stage is that it helps the unit run at top efficiency even when the outdoor humidity is in the moderate range. that's because the 2nd radiator (2nd stage) pre-cools the returning water from the first radiator (before it re-enters the tub). the unit could not be working any better. I'm getting awesome temps out of it. low wattage draw (under 100 watts). be ready for summer! easy to make and use! please comment, like and share 🙂👍

The "cube" part or "water chiller part" of the unit is a re-design of a previous model (used in earlier direct and one-stage models). I reduced its height and widened the water holes to 9/64" (9 per tube) 36 in total.

a few cool things...

🟢 these units are 3-in-1 meaning that they can be run 3 ways... as "Direct" evap units (no radiators, 1 pump, 1 fan), "One Stage" indirect units (1 radiator, 2 pumps, 2 fans) or "Two Stage" indirect units (2 radiators, 2 pumps, 2 fans).
🟢 these units can double as air humidifiers. you just use without the radiators and use the cube part indoors.
🟢 these units can double as outdoor evap fridges. you just drop your items inside the cube part. (the air inside the cube stays as cold as the pad).
🟢 these units can be DC powered (using solar panels or batteries etc.) just use 12v DC fans and pumps.

👍 for an extra blast of cold air you can add ice or ice blocks to the tub! (temporary but effective while it lasts)

🔵💦 the 9/64" water holes give the pads a fuller more complete saturation (originally 3/32"). in other words, all 4 pads now stay fully saturated no matter how hot and dry it is outside (plus the holes will never clog).

**first half of video shows the unit and its performance (including lots of water, air and pad temps). that's followed by a quick talk-thru of how (and why) the whole thing works. and lastly i show a complete disassembly of the unit and show everything that's needed to make it. lots of details and specifics included.

*Best way to get the tubes inside the home is to place the unit just outside of a window and the "fan with radiator" just inside near the window. then use a small piece of 1"x4" lumber mounted in window with 2 holes drilled in it for the tubes. works perfect. just cut wood to the length of window, feed the pipes through the holes, drop wood in and shut the window down onto it. makes a good seal.

one last thing, it's very portable. the whole thing can be disassembled and put into the tub in about 2 minutes. everything fits (other than the table fan). then just snap the lid on the tub and you can easily take it with you (camping for example).