Burnedout

How to Make an Airconditioner at home

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This would actually cost you more than just running an AC.

 

You'd need to cool the water somehow, which means a constant supply of ice or some other form of refrigeration, you'd need to power the fan and the [not shown but necessary] pump because it won't work to cool anything unless there's water flow, you'd need to be using bleach or something similar to keep the water from growing and becoming a health hazard, and it would be less effective than a standard AC unit and wouldn't do as good a job cooling an area.

 

It would actually cost less in the long run to just buy one of those window mounted or single room AC units.

 

Plus, an AC unit is less effort, as you'd constantly have to be dumping out spent water with this.

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Yawn. Let's see some numbers.

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5 hours ago, older said:

Yawn. Let's see some numbers.

 

Fine.

 

A 5,000 BTU AC uses about 550 watts an hour, which is about $0.12 per hour. That's about $1.60 per day if it runs for 24 hours. This assumes it is constantly running for the entire 24 hours, and not if it is set to shut down when it reaches a certain temperature, as most AC Units will do. So the actual cooling cost will likely be lower than that.

 

I'll give the fan system the best possible chance by assuming a 5 gallon cooler instead of just a bucket or something. Using a smaller container would actually cause the ice to melt faster, so it wouldn't cost less. It might not cost any more, though it might depending on circumstances, but in the end it would probably cost roughly the same and just require more upkeep.

 

Tap water costs about $0.05 per gallon. So we should assume that on a hot day, a 5 gallon cooler of ice water will probably last roughly 2 hours, particularly if it is circulating through a pump and being used like this, it would be gaining heat faster than it would if it was just sitting and holding soda. Once what is inside of it cools, a cooler will hold temperature pretty well, but if you've got a constant flow of water pumping through it that is gaining heat, as it would be in this case, it is another story.

 

Plus, you'd have to start with ice water, and not just ice, which means it will melt faster. That's $3.00 for 24 hours. Already almost double just running a 5,000 BTU AC unit for the same amount of time.

 

You might get 3 hours out of this if you're willing to put up with a tepid cooling for a bit. So, $2.00 for 24 hours, at best. That's just for the water.

 

Plus, you're going to need a constant supply of ice, which means making a constant supply, or buying it in bags in bulk. This also costs money, making it is cheaper, so we'll go with that.

 

Yes, your freezer is already probably running, but it requires more energy to keep temperature when making ice than when simply holding what is inside it at temp, and you'll have to be making ice in bulk. So there's another $2.00 per day if I'm being generous on top of that because you have to keep making enough to refill or refreeze whatever it is you're using to hold the water you're pumping through the pipe around the fan multiple times for the same time period.

 

Even if you're using ice packs you're still paying more to keep a supply frozen than it would cost to just run a 5,000 BTU AC, which would more effectively cool a larger area.

 

The cost of running the fan and pump is negligible, let's say another $0.15 for both for 24 hours, it's the water and energy cost for making enough ice to keep it going that really kills this.

 

There's also the humidity factor. The fan will actually be less effective for cooling because it will generate more humidity than an AC unit will. It will also create a mess by creating a pool of water around wherever you have it set up. An AC unit will circulate and pump out hot air and a lot of the humidity that the cooling generates. It also drains excess water created by condensation or contains it depending on the type of cooling unit.

 

If it contains it, it will need to be drained on occasion, but still much less often than the fan would.

 

This is not only more expensive, but also requires more effort and is less effective.

 

Just bite the bullet and buy a cheap 5,000 BTU window mounted AC unit or a portable AC unit rather than do something like this. The up front cost is more, but it's less effort and cost in the long run.

 

I could see this working in an emergency as a temporary solution, but no one is saving money doing this instead of using an AC.

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Contra:

I support your position. What I meant was numbers on the fan thing — how many degrees it would drop the air passing through. I'm with you on the efficiency of it. I don't see the fan gadget being anything more than a band-aid for someone stuck in a hot office or a warehouse workstation.

 

Here in the arid west we use evaporative coolers in many places. I've got one on my shop. When the humidity is 20 percent or less, the incoming air will be at least 15 degrees, and sometimes 20 degrees, cooler than the outside. But the drawbacks are increased humidity inside and a loss of efficiency when the outside humidity goes much over 25 percent. Most of the time I leave the front shop door open to keep the humidity level tolerable.

 

Something I've learned over the years is that there are many Youtube d.i.y. videos out there that aren't supported by facts, good engineering, safety, or common sense.

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5 hours ago, older said:

Contra:

I support your position. What I meant was numbers on the fan thing — how many degrees it would drop the air passing through. I'm with you on the efficiency of it. I don't see the fan gadget being anything more than a band-aid for someone stuck in a hot office or a warehouse workstation.

 

Here in the arid west we use evaporative coolers in many places. I've got one on my shop. When the humidity is 20 percent or less, the incoming air will be at least 15 degrees, and sometimes 20 degrees, cooler than the outside. But the drawbacks are increased humidity inside and a loss of efficiency when the outside humidity goes much over 25 percent. Most of the time I leave the front shop door open to keep the humidity level tolerable.

 

Something I've learned over the years is that there are many Youtube d.i.y. videos out there that aren't supported by facts, good engineering, safety, or common sense.

 

We agree then. This is a terrible idea for a lot of reasons beyond an emergency and extremely temporary cooling solution.

 

Still, I went and did the math anyway, so if nothing else that's the nail in the coffin of this being a viable cooling solution.

 

As for the amount of cooling it would actually provide, it would depend on a lot. How cool you were keeping the water you were pumping, then length it would have to travel to reach the piping [a clear tube is about the worst possible choice to move the water], the ambient humidity level, the size of the area you were cooling, whether it is enclosed or not, what kind of air circulation, etc...

 

If I had to estimate, in a 90°F room, assuming you're using well chilled ice water, you're probably looking at a 75°-80°F output at best. This is assuming you're sitting pretty much directly in front of the fan's airflow within five feet of it. The air doesn't have much time to cool just blowing over the coils once so the effect would really be minimal. AC units push the air through several layers of coils and circulate it a bit within the cooling area to chill it before venting it. It is moved past the cooling coils several times before being put into a room. They can also pump out warm air depending on the model.

 

The rigged fan would probably work in a large closet, say a 6x6 space with the door closed and no open windows, beyond that, it would probably only cool what it was blowing directly on. In a small space with little circulation bringing in new air, the fan would cool the room by pushing the same air through it repeatedly and cooling it a bit more each time, which would eventually cool down the room. It would take a while to cool the room even in optimal conditions, and unless you want to suffocate there would be some efficiency loss due to air coming in through the crack under the door or through some other form of ventilation.

 

So, assuming optimal conditions, it would lead to a very damp roughly 70°F closet sized room on a 90°F day.

 

In a larger space it would probably actually heat up most of the room due to the humidity it would create.

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Reminds me of that saying: "Marriage is sleeping in a room that is too cold, next to a person who is sleeping in a room that is too hot."

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