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/sci/ - Science & Math

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File: 283 KB, 1280x960, ac.jpg [View same] [iqdb] [saucenao] [google]
1559406 No.1559406 [Reply] [Original]

Sup /sci/

I'm in the fucking dog days out here, and I have no A/C in my apartment.

I made one of these, any thoughts on improvements for it? Aside from doing better putting it together, it was fucking hot and I wanted it done.

It works pretty well for making 1 room really cool.

>> No.1559436

is that suppost to be a homemade ac? I am assumeing that the fan and the metal is the condensor.

>> No.1559443

http://lifehacker.com/search/%23airconditioning/

Go and read, anon

>> No.1559444

you just pumping water through the tubing op?

>> No.1559453

.... is that your cooling element from your freezer? Are you pumping freon or cold water thru it?

>> No.1559460

Swamp coolers work by running air over water. The heat of evaporation cools the hair down. Maybe you can find some way to run the air over the water directly.

>> No.1559462

>>1559453
nope, just bought copper tubing from the hardware store and ran it through the fan guard.

>> No.1559457

>>1559444
yep, Ice water through it. Working out ok so far, could do more though I'd hope.

>> No.1559471

Mechanical engineer emphasis on energy and ac - you need a phase change, or you're not gonna get shit for cop

>> No.1559472

>>1559406
More tubing. The more surface area you have for air to flow over, the better.

>> No.1559473

get another one of those 20$ fans and make another one

>> No.1559480

How does it work?

>> No.1559483
File: 18 KB, 386x384, wat.jpg [View same] [iqdb] [saucenao] [google]
1559483

>>1559471

>> No.1559489

Pull the radiator out of an old junk car, clean it out, and run water through that, sandwiched between two fans in a push-pull configuration. Should be free and will work 1000% better.

>> No.1559490

Anyone has a guide on this?

>> No.1559495

>>1559471
What the fuck are you talking about? Fucking engineers, complete idiots. Again physicists demonstrate superiority by applying knowledge to real world problems, and not reading from blueprints.

>>1559472
Add salt to the ice bath. It will lower the temperature and you will have cooler air.
Also, wider pipes will get a greater volume of water flowing and increase surface area, might be something to consider, although how much of a benefit you'll get I'm not sure, and you'll need a bigger reservoir.

>> No.1559503

Put one of these behind/infront of the fan. It will work better than ice water, i promise.
http://lifehacker.com/5313401/hang-a-damp-towel-to-cool-a-hot-house

>> No.1559508

>>1559406
Maybe a cone shaped cowl and an elongated coil of the tubing inside?

>> No.1559512

>>1559406
Just buy another fan.

>> No.1559550
File: 395 KB, 465x421, 1280836038099.png [View same] [iqdb] [saucenao] [google]
1559550

>>1559495
he's right, ice water run through a coil is less efficient and less effective than a phase change system, although an ice system is still workable. a longer length of smaller diameter tube will actually have a higher surface area to fluid flow ratio, and will increase efficiency of a given ice/water volume.

op, take into consideration the humidity. is it very dry? if so, a swamp cooler may serve you much better, since it works by evaporating water into the air rather than condensing it. conversely, if it's really humid, the type of system you have would be more effective than a swamp cooler.

i have an artesian well at my house, so i don't pay for water, and it also comes up at about 42 degrees fahrenheit, so i run it through a radiator for nigger air conditioning, cools my entire house for 1/4 the energy cost of an air conditioner.

>> No.1559551

>>1559512
Fans increase the temperature of a room due to air resistance and motor dissipation. Don't get another fan. Drape a wet towel near the fan.

LISTEN TO ME! I AM QUEEN OF THIS THREAD! D:

>> No.1559567

>>1559495
adding salt will lower the freezing point of the water, which will allow you to freeze it at a lower temperature, which will increase the efficiency of the cooler, but just adding salt to ice will not make it any more efficient.

>> No.1559575

>>1559551
i agree, another fan will not help, but not for the reasons you think. the limit in his system is the surface area of the pipe, not the amount of air flow. also, the motor in the fan will contribute about ten watts of heat, which will not contribute in any measurable way to the temperature of the room. friction of the blades? no, absolutely not.

>> No.1559582

>>1559567
Ice from a freezer is typically around 0f. Liquefying it with salt will allow it to flow through the pipe.

tl;dr Liquefying frozen water with salt will allow hypo-freezing water to flow through the pipe, instead of hyper-freezing water.

>> No.1559595

>>1559550
I was considering that while thin wires have favorable surface area per unit of flow, the temperature of the water also decreases more quickly, and heat transfer is of course more efficient with a greater temperature difference. Again, I don't know how wide/narrow the tubing has to be for a difference to be noticeable.

In essence this becomes a difficult maximization problem involving potentially a good amount of college math.

>>1559567
>Does not know what an ice bath is.

>> No.1559601

>>1559582
makes sense, although you could reach the same result by putting salt water in the freezer (since it wouldn't freeze), and you would avoid the process of having to melt the ice with salt.

>> No.1559610

>>1559567
>>1559495

ok you dumb shit

adding salt will increase performance but not increase cop

infact the cop here is irrelevant because this shit is not a complete cycle. You're fucking cooling the water using you're freezer. It would be more efficient to just open you're freezer and stick the fan inside there.

Ya and you're a fucking idiot. I did research with different refrigerants considering phase changes vs non phase changes. COP jumps about 2 when phase changes get involved. Look at the TS diagram fuckin retard

>> No.1559614

>>1559601
This is true.

>> No.1559625

>>1559610
Actually that would yield a net increase in temperature, as the compressor would be continually running. The cooling system in the freezer is nowhere close to 100% efficient, so it's generating far more heat than it is removing.

>> No.1559626

ITT: People who fail to understand the concept of a closed system.

>> No.1559628

>>1559610
agreed, although if the freezer is in a different room than the cooler, the system works, albeit with an awful, awful cop
captcha: groan of technology

>> No.1559630

So OP's "cooler" is just a loop of ice water running past a fan?

is the freezer that made the ice, in the same room as the cooler is running in?

coz to cool down the room, you have to have somewhere to exhaust the unwanted heat to.

Otherwise it's like trying to cool down the kitchen by running the fridge with the door open. (ie: Doesn't work).

>> No.1559634

>>1559610

you're tubing is all wrong, you want the hot water to start from the top and work you're way down.

Don't let the pipes cross link or touch, or else hot water pipes will be transferring energy to cold water pipes.

>> No.1559661

Buy a window unit on craigslist for 50$ OP

>> No.1559667

>>1559575
The fan blades are pushing viscous fluid in the room around, which imparts energy to the air, which will cause the temperature of the air to rise. Fans are incredibly inefficient in this way. Also, a fan like that is probably not a 10 watt fan. It's likely a 60-120 watt fan, and nearly 100% of those watts are eventually turned into heat.

>> No.1559670

>>1559625

K idiot - you obviously insulate the cold body of the freezer to a separate room, the compressor will be pushing heat out of the cold body. Thus allowing temperature from cold to hot.

>> No.1559694

>>1559667

fan blades should be irrelevant as heat being absorbed by the cold water would be far more significant than the heat being generated by the friction of the air

compare heat capacities of air and water

fuckin physics retards in here

>> No.1559690

Yhe cost of your ice will be higher than the cost of running an airconditiner. All your doing is paying someone else to expend the energy to cool the water to ice AND transport it to the store AND giving the store a cut in the action.

If the ice comes from your freezer then your are moving heat from the water into your home and you really aren't helping things. I suppose if its cooler at night you could freeze over night and use the ice in the day doing to the heat like what a capacitor dose to ac current.

>> No.1559712

>>1559694
Adding a second fan without adding any tubing won't do anything except increase the heat delivered to the room.
The most efficient way to cool a room is to change the phase of a material. The heat of evaporation of water is huge.
Hanging a damp towel in the room or near the fan will cool the room faster than plastic tubing with ice water will.

>> No.1559716

this thread doesn't make any sense.

i can't even tell if OP is here still.

>> No.1559728

>>1559716
I am, just got back to it.

>> No.1559741

>>1559728
If you aren't hanging a damp towel in your room by now, I'm going to come over there, break through your window, hang 3 large, wet beach towels in your room, and then eat ice cream out of a tub while sitting on the edge of your bed, crying about my problems.

>> No.1559750

>>1559712

agreed - what thats doing is working similar to a dry and wet bulb temperature, you're focusing one small part of the room with a lot of water, thus increasing the relative humidity. Liquid water on the towel is going to evaporate into the dry air causing a cooler surrounding. Based on the original humidity of you're room, the temperature difference may only be around 2 or 4 degrees

like I said, emphasis on energy and ac.. you idiots got nothing on me

>> No.1559759

>>1559741
whats it like being a 40 year old man pretending to be a woman on an anonymous forum?

>> No.1559760

spend 3 bucks to buy a tube bender. getting it bent without any kinks will increase the efficiency of your system.

Also you want at least wise as much tubing.

>> No.1559766

>>1559759
I'm actually 20.

>> No.1559771
File: 115 KB, 300x400, 1278009975941.png [View same] [iqdb] [saucenao] [google]
1559771

OP here,

ok then, mid day heat tomorrow - hang damp towels with windows open?

I'm looking at you >>1559750


lol@ captcha: immense faucet

ps thanks guys

>> No.1559778

>>1559766
whats it like being a 20 year old guy pretending to be a woman on an anonymous forum?

>> No.1559781

>>1559771
Probably not with your windows open if it's very hot outside. Hang the towels near a fan or something, and then open the door to the rest of the house every once in a while to balance out the humidity when you replace the water on your towels.

>> No.1559787

>>1559778
Spoiler:

I'm a trap

>> No.1559801

>>1559787
whats it like being a retarded freak of nature?

>> No.1559812

>>1559771

windows closed
>>1559781
>>1559781
>>1559781
>>1559781

listen to this person wtfffff shes right

>> No.1559815
File: 133 KB, 354x363, feels-good-man.png [View same] [iqdb] [saucenao] [google]
1559815

>>1559801

>> No.1559823

LOL WHITE PEOPLE WHO NEED AIR CONDITIONING

>> No.1559830 [DELETED] 

>>1559771

windows closed
>>1559781
>>1559781
>>1559781
>>1559781

listen to this person wtfffff shes right
FTFY

>> No.1559844
File: 24 KB, 268x312, businessman.gif [View same] [iqdb] [saucenao] [google]
1559844

>>1559823
I know rite?

It is SUPER out of the ordinary when we can't afford central-air in our homes.

What can I say, I just moved in to my new place.

>> No.1559860

Hey guise if you add enough tubing for an infinite period of time would you eventually create a series of tubes that forms the internet?

>> No.1559866
File: 83 KB, 350x445, products-heat-exchanger-rth-b.jpg [View same] [iqdb] [saucenao] [google]
1559866

Redo the tubing using a smaller diameter and having it go back and forth in an s pattern from top to bottom. Something like the pic. If you use two layers like that, you want the water to enter the side away from the fan and leave the side near the fan. Definitely get a tubing bender to make it smooth and even. You want as much tubing in front of the fan as possible. You could even solder some copper fins to it if you want to get really crazy.

Alternatively, if you can salvage a small radiator, that would work even better.

Basically, if the return water isn't room temperature, you're not getting the best efficiency you can with your coil.

>> No.1559872

>>1559823
LOL NIGGER LIVING IN DETROIT

>> No.1559907

Put a grid in front of the tubing to slow the air. This increases the pressure of the air around the tubing, increasing heat transfer.

>> No.1559946

>>1559872
Actually I'm a chink who doesn't sweat unless it's at least fucking 30 C. If it does then I just go in the basement, or you know go for a fucking walk.

>> No.1559975

>>1559946
I'm white and I don't sweat until it gets that warm either, but where I live thats not very warm at all. It was over 38 where I live today and inside the house with no AC it will get over 40.

>> No.1559991

Placebo fan

>> No.1560086

>>1559457

I used to do this at my old place that had no AC and there was a grocery store a block away that sold cheap ice blocks.

you can make the water colder by making it a brine solution, especially if you can get a hold of some CaCl2, and also if you run a fan on the water's surface it will evaporate the water and give you more cooling power due to phase change.

>> No.1560120

>>1559866
>Basically, if the return water isn't room temperature, you're not getting the best efficiency you can with your coil.

lol you have a shitty grasp of thermodynamics, the inlet and outlet temps of the radiator are mostly irrelevant when it is a closed system with a reservoir. if the return water is room temp then you will be getting shitty efficiency and you could sink a fuck ton more heat if you up the flow rate.

>> No.1560134
File: 11 KB, 394x319, sisko-facepalm.jpg [View same] [iqdb] [saucenao] [google]
1560134

>>1560120
>>1560086
>>1559866

>> No.1560151

>>1560120
That's wrong. Heat transfer is slow so you need to slow the flow rate to maximize efficiency. Return water being room temperature means that the fan is WORKING FINE!

>> No.1560161

>>1560134

u mad?

where I live it gets hot enough to need AC about 7-10 days a year. Ice blocks in a CaCl2 solution gets down to 20 degrees below zero pretty easily and if you run it through a car radiator it is a fukkin cold air BLAST, and through a device like OPs it still creates a nice sub-ambient breeze.

>> No.1560165

i have two of these cheap box fans like in OP's pic. i might try this.. what method is cheapest for pumping water thru the pipes?

>> No.1560170

>>1560151

no. I'm not sure if you are trolling or not but what you just said is completely retarded.

>> No.1560182

>>1560165

if you are in US you can pick up small cheap fountain pumps at harbor freight for under 10 bucks. otherwise fish stores will have pumps for like 20 bucks.

>> No.1560185

Use aluminum plates. Use copper tubing to transfer the water about, but use it to cool alum plates. The plates will cool the air better for the following two reasons:
Low specific heat. Alum will lower in temp really quickly, cooling air better. Higher temp diff will increase heat current. It will also heat up quickly (due to air) increasing heat current to copper tubes/water.
Plates have increased surface area. More area for air to hit and cool.

>> No.1560199

>>1560185
But the water will evaporate.

>> No.1560216

>>1560185
cut pop cans in half and fold them over the copper?

>> No.1560217

>>1560199

Wut? You crazy.

>> No.1560222

>>1560185

...

why are people on 4chan always so fucking bad at thermodynamics

hiding thread before I mad

>> No.1560229

>>1560216

Don't just fold them around. Make flaps that the air has to slide along and pass by.

>> No.1560233

This thread is over, folks. We've already established that phase change materials (swamp cooler, water + towel etc.) are the best way to reduce the temperature of a room. Thanks for playing.

/thread

>> No.1560236

>>1560216
You can't solve the problem by just covering it up. Copper is the problem here. Replace all the tubing with aluminum.

>> No.1560240

>>1560233

>implying a radiator such as OPs can't be used in a partial/full phase change setup

>> No.1560248
File: 15 KB, 200x225, rage.jpg [View same] [iqdb] [saucenao] [google]
1560248

>>1560236
>>1560236

>> No.1560249

>>1560240
>Implying it can

>> No.1560251

>>1560236

Covering isn't a problem, copper actually has better heat conductivity than aluminum. Copper tubing is fine.

>> No.1560256

>>1560240
If i see it done more efficiently than hanging a towel, I will leave the internet.

>> No.1560258

>>1560251
Wrong. Lead has the best thermal conductivity.

>> No.1560261

>>1560249

large open-topped reservoir with fans blowing to evaporate a fuck ton of water, run water through copper tubing. that's only the first way, there are many ways to use phase change through a radiator.

>> No.1560265

>>1560258

wrong.

diamond has the best thermal conductivity.


...known to man.

>> No.1560277

>>1560256
A window fan cools the room faster. Now quit the internet forever.

>> No.1560287

>>1560277
A) that's not part of the deal
B) you're fucking wrong.

>> No.1560330
File: 8 KB, 246x198, swis.jpg [View same] [iqdb] [saucenao] [google]
1560330

>>1560277
plz an hero

>> No.1560336

>>1560287
Circular thinking gets you nowhere.

>> No.1560413

>>1560233
so thats why modern HVAC systems work by blowing air through a box full of damp rags hanging inside?

>> No.1560474

just buy an automatic air freshener.
mod it to use water and spray in 5-10 seconds interval.
also buy an exhaust fan. to reduce air temperature.

increase the humidity.

>> No.1560496

>>1560474
That sounds like it would work well in an arid environment but not if its already humid and hot as fuck. I donno where OP is, but I live in South Texas and anything that that works by evaporation like swamp coolers or hanging towels and stuff only makes it worse. I just fuckin run my AC but energy bills get high and anything that can cool the air cheaper without making the place more damp than it already is encouraging mildew is interesting to me.