As the summer progressed, I felt like I needed to improve my initial design. Luckily enough the science department had just thrown away an old freeze drying machine which had a perfect radiator. A few minutes crouched by the dumpster with some hand tools, some minor adjustments, and the Black Beauty was born.

Here’s the overall view of the unit. A high speed fan pushes the air through the perfectly sized radiator, and water flow rate is controlled by a small hand valve.

The radiator itself was horribly filthy when I first took it off, but a quick soak in some warm water and light detergent took care of it. The copper tubing inside the radiator is the exact same diameter as the copper tubing I used when I first built my original homemade air conditioner, so no need to change up the vinyl tubing.

I placed the fan fairly close to the radiator itself, and it works great. I typically put the fan on the medium or low setting, as I notice little benefit from the high speed setting other than increased noise.

The radiator was almost perfect, it only needed to be raised by a centimeter or so to align with the fan. Turns out old original Nintendo cartridges do the trick just fine. (For the record, that’s Teenage Mutant Ninja Turtles and Marble Madness. Don’t worry, I have other copies.)

Cold water is supplied from an outside garden hose. More detail can be found in the water supply section.





To calibrate the valves, the small hand valve inside is first opened wide and the garden hose opened or closed to find an appropriate upper flowrate. Then the hand valve may be used to vary the water flow or turn it off entirely.

The nice thing about this new setup is that all control is now done from inside the room. Starting and stopping the unit is far more convenient, which leads to more efficient water usage. The performance of the unit is drastically improved over the old design. Less water is needed, and the room cools quicker.