Water deicer

[bdstech2]

How can I build a water deicer to keep water from freezing in a 20oz bottle? I have birds and trying to keep water from freezing.

 

[Papabravo]

Years ago I worked in a biochem lab and they had a cool gizmo that was basically a plastic coated magent and a unit which produced a rotating magnetic field. You put the magnet into a solution in a flask or beaker then put it on top of the unit. Hit the switch and the little magnet starts to rotate at a variable speed. If the water is moving it can't freeze. Maybe not elegant but it beats poisoning the birds with ethylene glycol(antifreeze).

 

[Roff]

Years ago I worked in a biochem lab and they had a cool gizmo that was basically a plastic coated magent and a unit which produced a rotating magnetic field. You put the magnet into a solution in a flask or beaker then put it on top of the unit. Hit the switch and the little magnet starts to rotate at a variable speed. If the water is moving it can't freeze. Maybe not elegant but it beats poisoning the birds with ethylene glycol(antifreeze).

I'm betting moving water will freeze. If you remove energy from the water faster than you are putting it in, it will eventually freeze.

 

[evandude]

how about a small aquarium heater?

 

[Papabravo]

I'm betting moving water will freeze. If you remove energy from the water faster than you are putting it in, it will eventually freeze.

He didn't state any requirements. If by removing energy you mean lowering the temperature then yes moving water will freeze but at a lower temperature then water which is standing still.

Water can also be supercooled in the absence of nucleation sites to temperatures lower than 0 degrees C (32 degrees F). Toss in a miniscule amount of impurity and it's like Ice-9

 

[evandude]

Toss in a minicule amount of impurity and it's like Ice-9

like a bird?

 

[RadioRon]

one way to keep the water warm without using a resistance heater is to circulate it through the ground at a depth where the ground is not frozen. Kind of a mini-geothermal system. Of course, this means running a bit of tubing to and from the container and having a tiny electric pump circulate it, so its a bit complicated. But just pushing the water through a buried tube will warm it up enough. It works for my swimming pool just fine.

 

[Roff]

Water can also be supercooled in the absence of nucleation sites to temperatures lower than 0 degrees C (32 degrees F). Toss in a minicule amount of impurity and it's like Ice-9

That happened to me once. I got in my car one winter morning and touched a bottle of water. It froze INSTANTLY!

 

[mattadler]

How about using a peliter module.

 

[Sceadwian]

Peltier heater/coolers are expensive, nichrome wire isn't. A simple piece of nichrome say ripped from a toaster, and a thermistor as biased for a transistor will easily keep the water from freezing. Cheaper easier and just about idiot proof. You just have to water proof the electronics with a potting compound.

 

[Oznog]

Water can also be supercooled in the absence of nucleation sites to temperatures lower than 0 degrees C (32 degrees F). Toss in a minicule amount of impurity and it's like Ice-9

Oh yeah that's a good idea. The bird drinks and it turns to ice in its throat!
Probably freezes him to it too.

Watch it happen:
https://www.youtube.com/watch?v=V3R4VAdCbTg

 

[Sceadwian]

It would require distilled water. That's not likley to form in the dish =) Any agitation in the dish would only help for temperatures relativly close to freezing, they wouldn't work on days when the temperature drops more than a degree or two bellow, unless you really agitated it a lot. Which is more likley to turn the bird bath into a bird blender. A simple resistive heater and a properly located thermistor is easy enough to implement anything else is really too complicated.

 

[G8RPI]

Hi,
how about a small PTC thermistor? As the temperature goes down it will draw more current and heat the bottle. If it's a glass bottle, just attach it to the outside and insulate the bottle. For a plastic bottle you would be best attaching it to a small metal plate bent to fit the curve of the bottle.
By correct choice of thermistor and supply voltage you can adjust the temperature. Electrically you just connect it to a supply, AC or DC, a small mains transformer would be ideal.
G8RPI.

 

[Shax]

Peltier heater/coolers are expensive, nichrome wire isn't.

Peltiers are cheap (60mm x 60mm for 12$US), the PSU required to get them to function is the expensive bit! I have an Alinco 32amp variable switch mode PSU that gets my peltier to -38 celcius on the cold side but it draws about 14 amps at 12v.

Why not use a 22R 25w metalclad resistor? Hook it up to a 12v 1amp wall wart and dunk it in epoxy to insulate the ends. That could be submerged in the water to keep it liquid.. Viola, hot tub for birdies!

 

[stevez]

Keep in mind that stirring the water by any means adds some heat. Whether or not it's enough must be determined.

 

[ParkingLotLust]

Wrap the bottle in a coil and connect it to a 12v supply. Ive seen it on tv before, where they use induction to heat a piece of metal before quenching it. Should just be able to use a coil to heat up the water a little bit with a magnetic field, no?

 

[Sceadwian]

Induction heating requires a conductor to work on. Potable water isn't even close enough to a good conductor to provide any decent heating, and if it did you'd just as likley end up microwaving the birds..

 

[ParkingLotLust]

Worth a shot

 

[Sceadwian]

Seriously you'd have to use microwave frequency energy to heat water like that =) That's what a microwave is, a RF source that's at a natural harmonic of water so it absorbs the energy prefrentially. You WILL cook the birds, or give them cancer. Or people that sit a round the bird feeder for a long period of time. As well as jamming every Wi-fi or 2.4ghz cordless phone within a few miles.

 

[Sceadwian]

Induction heating is most effective closer towards audio frequencies. I think induction furnaces work at AC mains frequency up to 10khz or so. Anything higher than that and you'd start causing nearby AM receivers to burn out.