Salt water in bottle efffect on freezing

..."Does this bottle of unfrozen saltwater make it warmer in the tank water? No! The temperature of the liquid saltwater is just as cold as the freezing freshwater. The idea that the proximity to the saltwater somehow keeps the freshwater from freezing is a myth. However, the floating bottle does agitate the surface which helps prevent and ice skin from forming and horses can push the bottle down with their nose to break a hole in the iced over tank."...

https://www.horsenation.com/2018/01/23/4-low-tech-ways-to-fight-frozen-water-troughs/#:~:text=The%20idea%20that%20the%20proximity,Myth%20busted%3F

I think you are right.But IF,and that is a big IF,the temperature of the air inside of the bottle drops below the temperature of the freezing point of the salt water before the fresh water temperature has dropped that low,then the salt water would shed some latent heat before it could freeze.There might even be a point where it was not cold enough outside/inside of the air in the bottle to have any effect,so the amount of salt would be critical for a certain temperature range.

i am sure the effect would be minimum,and that moving objects would have a much greater effect.

Anyway,What a beautiful animal!

Best way to go I think is a coal burning water heater

You can get coal cheap~ $40-50 a ton....30lbs a day ...a couple of tons should last all winter...

https://dsofpa.com/wp-content/uploads/DS_Brochures_SpecialtyBoilers_2021_ToPub_HighWeb.pdf

The power of fermenting hay is amazing.Put the water tank on top of a bale of hay that is insulated and protected from horse teeth and it will keep the water from freezing.

In the center it can be over 160F.

In England,they used compost and sawdust piles to make domestic hot water by putting copper coils in the center of the pile.

And of course,there were thieves that stole compost.

I left a bale of hay in the back my jeep all winter,and the windshield never frosted up,but all of the other vehicles did.

Seems like a lot of work, hard to control heat output....not sure how long it will work for....and then needs to be replaced...No I don't think this is a good way to go...though the composting process will produce heat, controlling it is another issue...and it's a one time shot with no defined length of service...not to mention methane fume seepage from the ground, and the threat of spontaneous combustion...

https://www.keelayogafarm.com/2019/11/10/water-heated-by-compost/

Under certain conditions… I would agree…

yet,..l if you ever in the dead of winter, cleaned off the inside of a silo that has frozen haylage sticking to the wall what the silo unloaders chipper could not take off, you expand on that hypothesis.

I wonder if the fact that the convection in the salt water is in the opposite direction to the plain water below 4°C, bringing heat from lower in the trough to the top has enough effect.

A simple vertical axis wind turbine without the turbine but just a "paddle" in the trough would do the job.

About the time you finished that, the wind would immediately stop blowing...haha

I remember a French guy on here described a savonius rotor made from two halves of an oil drum mounted on a car axle. Reckoned that it generated enough hot water for the family to shower everyday.

What was I thinking?

In the middle of Nebraska, where we get a lot of freezing during the winter, my cousin would get a small metal barrel and cut a door in the side. Add a smoke stack and start a small smoldering fire in it.

Of course you would need to feed it every night. And eventually the bottom would burn out.... But it did the job! ss

There is no magic, but sometimes mystery.

Energy is quantifiable, has many forms and doesn't vanish or appear. 80 Cal/gram needed to melt, or produced by freezing. Mass matters (including air) not temperature alone. Air is a lot lighter than water. Wind matters. Heat transfer rates. There are effects of insulation by ice and the layer of air over the ice. and the container and its support. Interesting but not simple problem. Do the animals drink at night?

They've been known to....

I'm thinking it might have to do with convection.

The air is colder than the water, which is colder than the ground. When the air is below freezing, ice forms on the surface. The maximum density of water is greatest at about 4 degrees C. As a result, as ice is forming, the water just underneath is at a higher density and sinks, convecting with less dense warmer water underneath. This convection blocks the transfer of heat from the earth to melt the ice.

(This blockage of heat transfer prevents lakes and ponds from freezing solid to the bottom.)

Fresh Water - Density vs Temperature

A partially filled bottle of salt water does not have this density reversal, and convection in the salt water can transfer heat to the surface, bypassing the convection in the fresh water and melting the ice on the surface.

Salt Water - Density vs Temperature

Here is a simpler and clearer way to explain it:

1. The temperature of the water (or ice) decreases from the ground up through the water to the air.

2. In the liquid, if the density of an upper layer is greater than the layer below, the water will circulate (convection). Thus, convection occurs if the liquid increases in density with decreasing temperature.

3. At 4 degrees C, the colder water above is less dense, so there is no convection above this point to transfer heat. Heat still flows slowly up from this point by conduction, which is far less efficient than convection.

4. Convection in the salt water bottles bypasses the 4 deg C barrier.