Nitpick about Fremen stillsuits

In Frank Herbert’s Dune, the desert-dwelling Fremen conserve water by wearing the “stillsuit,” a jumpsuit of some waterproof material which collects their sweat (and urine) for filtration and re-consumption.

Very clever. Why don’t they die of heatstroke? Sweat isn’t just one of nature’s little design flaws, like zits and ingrown toenails. Sweat is how your body cools itself: Evaporation is a cooling process, basic high-school bio. When your sweat evaporates, it takes some of your body heat with it. Pigs wallow in mud, cats lick themselves all over, dogs pant, because they can’t sweat and they need to cool themselves some other way. If you’re a human, and you’re wearing a waterproof suit that keeps your sweat from evaporating, and you live under a desert sun . . . you get the idea?

BTW: The stillsuit apparently does nothing to stop the body’s loss of water through respiration, which is significant – just breathe on a mirror and watch it fog.

IIRC, there’s a little nose plug, and people wearing stillsuits are instructed to inhale through the mouth, exhale through the nose.

Can’t help you on the heatstroke thing. Maybe they’ve got dozens of tiny little fans inside.

Plus there are also flaps that conceal your whole face except for your eyes, so even if you do breath out of your mouth, the moisture isn’t going very far.

As the sweat is pulled away into the suit the body does cool down. However, the suit becomes hot and radiates away the heat. You end up with a cool(er) body inside of a hot suit. Therefore sweat still works its magic, as does the still-suit.

There are face covers in the book. In fact, this is a significant plot point in the fourth book.

Re Respiration

If you watch the film, the stillsuits have a large black tube that is inserted into the nostrils. At one point, one character reminds another to breathe through their nose to conserve moisture.

If you watch either of the Sci Fi channel miniseries, the stillsuits have flaps covering the nose and mouth.

If you read the books, the suits have flaps aplenty. Fremen remind their children to close the facial flaps by saying “Guard every breath as your life.”

Re Heat

This IIRC was not explained in any of the adaptions. In the books, the Fremens wear a cloak of some high tech material. Depening on how it is worn, the cloak lets heat out but not in, or lets heat in but not out. The cloak can also be used to form a small tent.

Pulling away the sweat removes far less heat than would be removed by using body heat to cause the water in sweat to change state from liquid to gas. My opinion is that Frank Herbert just didn’t think of it. You’re correct, though, the still-suit does work by “magic.” :wink:

What are you getting at? Ok, so maybe they get a bit hotter than they would if they were wearing nothing at all. But it’s either that or lose all of your body’s moisture. I think keeping fluid is far more important. And besides, the Fremen have been living that way for hundreds of years. They can tough it out. :wink:

They have interstellar travel guided by floating, psychic people, force fields, laser rifles, and they ride giant worms, and you’re worried about a little heat?

It’s called “suspension of disbelief.” And “fiction.” Look it up.

This is one of those things that has bothered me ever since I first read Dune over 30 years ago. You wrap yourself up in black unbreathing plastic and go for a walk in a hot desert, and see how long you last.

It was an interesting concept, but I could see practical problems in trying to actually use something like that. Kinda like the equally implausible “ornithopters” in the book. Eventually I just accepted it as part of the background.

I always assumed that it was somehow like Arab desert dress. Arabs in the desert wear a lot of clothing, the idea being that a) it keeps sweat from evaporating too rapidly and b) compared to the heat of the sun, the heat inside their clothing is nothing. One problem with the stillsuit, though, at least as shown in the movie, is that it’s form-fitting. Arab dress is loose to allow for considerable air circulation inside. I don’t remember Herbert describing the stillsuit as form-fitting (but it’s been years since I read the books). In any case, if you can use a spice generated by a worm to bend space, getting air circulation in a stillsuit is a minor problem.

Finally, as one who’s worked in Tyvek in Louisiana in August, I can attest to the fact the the human body can adapt fairly quickly to considerable heat, as long as one remains hydrated.

I am not a Dune fanatic, but the last I heard some of them discussing the movies, the general concensus was that the movies were not necessarily accurate in depicting certain aspects of the books, especially the stillsuits.

Maybe the stillsuits use active refrigeration to keep people cool. If the outer surface was a solar-cell material, and the energy generated was used to power a reverse-thermocouple heat pump, that might work. Though how semi-barbaric desert nomads can build such a thing, I don’t know.

Per the books, the stillsuits are driven by a system of pumps in the heel and legs of the suit, which provide the work necessary to run the reclamation system (both fluid and solid waste). It is certainly conceivable that this pumping action can also drive some sort of unspecified cooling system, like pumping an alcohol or freon type of fluid throughout the suit.

The stillsuit is simply a heat engine, and you can cool anything as long as there is an energy source to provide work (in this case, the foot pumps)

It’s claimed in the book that the sweat is allowed to evaporate as normal, underneath the watertight outer layer. In fact, this evaporation is a critical part of the purification process, and what puts the “still” in the stillsuit. The book conveniently glosses over the fact that re-condensing the moisture would give off just as much heat as you lost in evaporating it, though. It’s conceivable that solar cells or the foot-pumping power some sort of active cooling, and such would be quite within the technological capabilities of the far-from-barbaric Fremen, but I don’t think there’s any indication that this is how the suits work.

Also incidentally, a cloak which passively passed heat in only one direction would violate the Second Law of Thermodynamics.

Incidentally, it is possible to withstand great heat so long as you remain hydrated, but the reason hydration is needed is so that your sweat can cool you off. So a system which effectively prevented you from sweating would do nothing to protect you from the heat.

I’m aware of this. I’d do a search, but can’t remember the name of the cloak. IIRC the stillsuit was just meant to conserve moisture (losing less than a thimbleful per day) it was the cloak that kept you cool.

Jubba cloak

You’re right, my bad. It’s so long since I read the books – should have reviewed them before starting this thread.

Well, I don’t think the Fremen actually made their stillsuits, or anything else more complicated than a crysknife. But they had some trade with the peoples of Dune’s few cities and permanent settlements, so there was a pipeline by which they could acquire manufactured goods, even those made off-planet. Happens today – I remember a picture from National Geographic of an Indian kid in the Amazon rainforest trying to solve a Rubik’s Cube (this was back when the Cube was a new fad).

Did you actually read the books? Stillsuits were, in fact, an item of trade between the Fremen and the cities… But in the other direction. The stillsuits of Fremen manufacture were universally recognized as being superior to those made by the cityfolk, and a Fremen wouldn’t be caught dead in one not made by themselves. I repeat, the Fremen were not at all barbarians, and only semi-nomadic. Sure, most other folks thought they were, but that just goes to show you how ignorant others were of the Fremen.