Homebrew Air Conditioning for Under $25

inkey string writes "Summer has arrived, and I've been busy slowly overheating in my student house without central air. I decided to put my thermodynamics classes to work however, and produced this ~24$ homebrew air conditioner. It'll cool a room to a comfortable level in 15-20 mins, and will run for a few hours on a garbage pail full of water. It's cheap, environmentally friendly (just fire the waste water off to your garden), and makes a good one hour project for a quiet evening."

Comments

MirrorDot

[eric434]

Next up, a $24 watercooling rig for his web server.

http://www.mirrordot.org/stories/5cb66a4a72a5269bc 29e9dd8f982b3da/index.html

Coral Cache

[Spy der Mann]

http://www.eng.uwaterloo.ca.nyud.net:8090/~gmilbur n/ac/

Will someone edit the submission to replace the URL, please? Sheesh.

No, it isn't

[Roadkills-R-Us]

A swamp cooler pulls the air through the actual water. It uses evaporation for the cooling effect. That's rather different than this, which is just a crude radiator. effect.

Congratulations

[overshoot]

At first I thought you'd reinvented the swamp cooler. On RTFL, however, I find that you've actually reinvented the 18th-century icehouse cooler, which is notably less efficient (like, where does the heat from the icemaker go?)

It didn't seem all that likely that most /.ers would care about evaporative cooling, since even in Arizona they only work part of the year (like now, although today the Phoenix dew point got up to 10C. I woke up just knowing it had gone up because the cooler was blowing full speed and it still wasn't all that cool.) Never mind next month when the monsoons start. AC time then for sure.

mirrordot

[kryogen1x]

Thank you mirrordot.

Re:Canada

[RobinH]

Dude, I'm in Canada... was 92 fahrenheit here on the weekend. Plus humidex.

Good show, but not a great idea...

[benjamindees]

Other than the obvious ingenuity involved in the creation of this device, the reason things like this don't exist in the real world is that they're hardly efficient. And comparing the purchase price instead of the operating costs of such a device is a sure sign you're missing something.

Air conditioners are unbelievably cheap and unbelievably efficient nowadays.

As others have said, this setup has all sorts of problems, from a reliance upon a source of ice that may very well be dumping more heat into the local environment than it saves, to wasting water.

Though this system doesn't use a pump, a recirculating system with a small electric pump could end up creating more heat than it saves.

If you're really bent upon saving energy in a cost-effective fashion, adding insulation is almost always efficient. Good blinds on the windows are also a great investment.

addressing all the flames/legitimate concerns...

[inkey string]

number one, yes i realise that in a closed system freezing ice to cool yourself off is foolish. this is why i make ice in the kitchen, and cool my room off at night.

which addresses the why no recirculation/you need an infinite supply of ice criticisms. this was designed to cool me off before bed, so i could fall asleep without wanting to kill myself. once the bucket runs out of water/ice, it just becomes a regular fan which is fine once the house cools off in the wee hours. plus i dont have to worry about knocking anything over in a morning daze.

ive rigged it up to a slowly flowing garden hose which will keep things cool indefinitely, but i find it easier and a bit cooler to just pick up a big bag of ice and dump it in when it gets really hot.

anyways, take it or leave it. and to the graduating chemmie that said he was ashamed to call me a student - come visit me at my office by the weef lab (e2-1311), im sure i can address any of your concerns to my satisfaction.

CostCo $50 for 5000 BTU

[jbridges]

Spend another $26, and buy a real airconditioner for $50 at CostCo.

It's $99.99 with an instant $50 off rebate at the register.

Less work too.....

Bend the copper using sand

[ishmalius]

I don't know if this guy ever took shop class, but the simple old trick of filling the part of the copper tubing to be bent with sand will help prevent it from collapsing from a too-tight bend.

Re:Minor nit

[racermd]

I hit this through the mirrordot link from above...

This is exactly how a good thermal heat-pump operates. However, a few "upgrades" would make this perfectly viable for a home of 1500+ sq. feet.

1: Make it a closed-loop system, or even a dual-loop system.
2: Use a good radiator and heat-block. Think of a water-cooling rig on a PC, but in reverse and a much larger scale.
3: Use the earth, itself, as both the source and destination of heat.

Most people that have done this for their homes use the earth as a natural heat sink. If it's new construction, they typically dig shallow, but wide. In a retro-fit, they'll drill deep and narrow. Either way, the earth holds a pretty steady temperature below 6-8 feet or so. All that's needed is a way to put heat into it when you want to cool off and a way to get heat out of it when you want to warm up.

This way, all that you spend money on is the electricity to pump the heat-carrying fluid/gas/whatever into and out of the tubes in the ground. If that isn't enough, a small furnace and/or A/C unit can supplement, if need be. Either way, the energy consumed from the utility companies is a fraction of "normal".

I have plans to build a new home in the next 3-5 years, and I'm looking at all sorts of alternatives to just about everything that consumes energy in a home.

1: Geothermal heat pump(s) for climate-control.
2: On-Demand, CNG water heater (i.e.: no tank to keep warm)
3: Solar-powered radiant heat (suplements forced-air from #1)
4: On-Demand lighting (sensors that detect room occupancy)

I'm missing a number of other things I could do, but the goal is to have a home with all sorts of modern conveniences while trying to reduce the energy usage associated with most of them. It's tempting to add a water-cooling loop to the climate-control system for the comptuers. They're already producing heat, so why not just send it directly to it's destination and avoid that pesky conversion to heated air?

Getting back on-topic, this guy hasn't done anything new. In fact, it's rather wasteful to just use a coil of copper tubing tied to the back of a fan. The fact that he's using ice water (as mentioned in other posts) does nothing to save energy costs. After all, he's got to power a freezer to make the ice to begin with, which offsets most of the savings. Never mind that the heat from the water (plus the heat from the machine, itself) went into the living space that he's trying to cool.

And that he's a student, and *probably* not paying for much, if any, of his utility costs. But I digress...