Can you dry clothes by freezing them?

Question

In freezing conditions, if you somehow get your clothing soaking wet, would you be able to dry them by wringing them out, letting them freeze, then shaking/hitting off the frozen water?

I was thinking about what you might do in this situation. Drying the clothing via evaporation requires energy that can only come from your body (assuming you can't make a fire). If you attempt to use the heat energy in the air it'll cause the water to freeze instead. But that got me thinking. Having the water in solid form may allow for its removal without energy expenditure.

So what happens when you freeze wet fabric of different types (fleece, wool, polyester, etc.)? Can you remove the frozen water fairly easily?

Answer 1

I remember someone telling me a long time ago that people in Greenland hang their clothes outside to dry at freezing temperatures without issues. No idea if that's true and I never tried. Anyway, from a theoretical point of view, this should work if the air is dry enough. This means that the water vapor pressure in the air must be lower than the equilibrium water vapor pressure at the air temperature. Or in other words: The relative humidity must be lower than 100 %, the lower the better. It may be a little counterintuitive, but the vapor pressure of frozen water is bigger than you may think, for example approx. 6 mbar at 0 °C. So there can be quite some evaporation over time even if you only use energy from the air in a well-ventilated/windy place and maybe some sunshine. Anyway, you would require some alternative clothes to wear in the meantime, so this may limit the practical use of this method, for instance during backpacking when you carry only very limited spare clothing.

Concerning hitting off frozen water, the Wikipedia page about Inuit clothing states:

Historically, Inuit used two main tools to keep their garments dry and cold. The first was the tiluqtut, or snow beater, a rigid implement made of bone, ivory, or wood. It was used to beat the snow and ice from clothing before entering the home. The second was the innitait, or drying rack. Once inside the home, garments were laid over the rack near a heat source so they could be dried slowly.

So apparently, beating off ice and snow can be a thing. However, I would suspect this will mainly work for ice/snow on the clothes surface, rather than if your clothes are completely soaked.

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One word about the technical freeze-drying process because it is mentioned in the comments: To my understanding, vacuum is not used primarily to speed up the process (at least in the most simple version where you do not heat your sample), but rather to keep whatever you dry frozen even if your room temerature is 20 °C or so. Too low pressures will indeed slow down drying because equilibrium temperatures and vapor pressures are very low then and only very little evaporation occurs. No need to carry a freeze-drying apparatus on the trail, luckily.

Answer 2

Ice sublimates about as fast as droplets of water evaporates under otherwise similar conditions. So in dry air frozen clothes will dry reasonably quickly.

Of course when drying frozen clothes you have the problem that the remaining ice is not wicked to the surface like liquid water, so the fabric hinders the transport of the water vapor from the interior slowing the process for thick garments.

And there is a risk with drying clothes that way: The frozen fabric may break (in the sense that the ice breaks and the forces involved tear through the fabric). So beating pieces of ice out of the garment may not be the best idea. My mother tells this as anecdote: As a teenager she lost several garments that broke when they froze on the clothes line in the winter and she took them down too early.

Answer 3

I'm born and raised in Canada. You can hang your clothes out to dry in the winter if you don't mind waiting (generally a day or two) for them to dry. You want a clear dry day with a good (but not too strong) wind. The clothes will quickly freeze and then the ice will slowly sublimate away. Sun and a breeze really help.

A freeze dried towel is very pleasant. Unlike a towel coming off a summer clothesline, where everything feels stiff, one that's been freeze dried is quite soft

Answer 4

Cold-weather clothes with good insulating properties do so by trapping a layer of air in small pockets within the material. Unless the garment is waterproof, these air pockets fill with water when it gets wet. When the water freezes, there is no particular reason the ice should move from the interior of the garment to the external surfaces where it can be removed - instead of a down-filled jacket, you'll have an ice-and-down-filled jacket.

You might be able to shake ice crystals off a thin material that's mostly surface area, but I don't see a practical way to get water out of a wet garment with any kind of internal volume, which is probably what you'd be wearing in freezing conditions in the first place.

Answer 5

Clothes do indeed dry on a line in freezing temperatures. Frozen air is usually dry. Ice sublimates. Willingly so, especially in direct sunshine. You're good.

At least you're good if the freezing weather lasts, because temperatures just a little above zero where you get fog and condensation are the worst. Even what was already dry will get damp.

Note that this is not a method to dry your clothes while you're waiting wrapped in a blanket, or overnight. We're talking a matter of days. It can even take the better part of a week. Obviously a light shirt will be dry sooner than a pair of jeans.

A determining parameter is the initial amount of water in the fabric when you hang it on the line - same as in summer, the less the better. You want a good starting position there, which means you wring the clothes out thoroughly and then there won't be any ice forming on the surface that you could break off. Peeling ice off isn't how it works. There'll be tiny crystals inside the threads that you can't remove mechanically.

And one thing to consider is that a temperature shock may make your clothes shrink. Wool in particular is sensitive to it (hopefully you know that washing in warm water and then rinsing in cold is a no-no for wool: use the same temperature in both steps), so I'd be wary about throwing it from even ice-cold water to frozen air as well, and absolutely not wash wool in warm water before hanging it to dry in the cold.

Answer 6

What the clothing is made of matters quite a bit. As a demonstration, soak a pair of blue jeans and a pair of wool pants in water and then freeze for 24 hours. The jeans will be a solid mass after that and I doubt any amount of airing would do anything at all. The wool, surprisingly, will still be quite pliant. I would try it out with different materials and see what you can find out.

Answer 7

The effectiveness of this method depends on the type of fabric. For synthetic materials like polyester, the ice may come off more easily, allowing for a quicker removal of frozen water. However, natural fibers like wool absorb more moisture, making it harder to remove all the ice without leaving some residual water. Additionally, the process of freezing and then thawing could lead to a more complex drying situation, as the clothes will need subsequent evaporation to fully dry, which is limited in cold conditions. Thus, while freezing can help with some water removal, it's not a complete solution for drying clothes.