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The leaning tower of Piezo
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A long time ago I took a trip up to Mt Washington in New Hamsphire. The temperature at the top was a hell of a lot colder than the temperature down below. A gift store up at the top sold little packages whose contents, when crushed inside the bag, would emit enough heat to keep your hands quite warm
(they were almost too hot to hold). The makers of lifejackets could add something similar to their product. They'd be embedded in the inner lining where someone treading water could trigger them as needed to warm the core of their body. It might just buy them enough time to get rescued before dying of hypothermia.
They are AIR activated.
http://www.heatmax....ands/technology.htm
[xandram, Jul 12 2006]
HotSnapz
http://www.hotsnapz.com/index.html
Not a big fan of the name, but these are the handwarmers we used to play with in middle school science class. [shapu, Jul 12 2006]
Sodium-acetate pads
http://www.howstuff...com/question290.htm
[Shz, Jul 12 2006]
Nasty, nasty weather up there
http://www.ruhr-uni...limusa/projmt_e.htm
[Shz, Jul 12 2006]
[link]
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While I think it's a great idea, I don't know if it will work in water. I linked the site which states that they are AIR activated. |
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Could use calium carbide. |
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I'm for it. How long would they last? |
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I'm sure they don't use air. If this is the same as those things where you crack the tile inside, there's no way for air to get in. However, I'm all for the idea. As long as we don't get people having to choose between third-degree burns and drowning. |
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[db] If you read the link, it acts like quick oxidation.
*They* said they use air, not me.
If all you smart guys think this can work, I'll give a warm bun life jacket. + |
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Could use hotsnapz and similar items...they're totally self-contaned and waterproof. [link] |
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Some handwarmers use the moisture in the air. I think they are based on iron filings and salt . . . |
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It seems to me you could apply the heat to a part of the body where it would be most effective at warming the blood directly rather than trying to warm a large area such as the entire chest. Neck? Head? Those would be good candidates since they are above water. |
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Sodium-acetate heat pads do the trick while diving. + |
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Too bad that gift shop at the summit is closed during winter... I'm going to assume you drove up, rather than climbed it unprepared. That's the nastiest weather in the world up there. |
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//That's the nastiest weather in the world up there.// |
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[Shz] I'll say. Mt Washington has recorded the highest sustained windspeeds on earth at over 200 mph. People have died by being blown off the mountaintop. |
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It's considered maritime weather, despite the altitude and distance from the ocean. The conditions are frequently worse than those at the poles. It's the only place I've ever enjoyed a hurricane on a sunny day. I climb it every year, sometimes in winter and I've had to rescue people there, but have yet to find a corpse (fingers crossed). |
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Shz - I took the easy way up - a train. Don't know if it's still running but I have a depth perception problem so driving mountain roads is no fun, and hiking takes too long. |
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When we drove up, I was shocked to find that one of the first things to see was a list of all the people who died up there!----or fell off. |
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The issue is with the heat that you are losing rapidly through the surface area of your body -- the simplest solution is a wetsuit. A wetsuit shirt/which can actually also keep you afloat would be better than a lifejacket |
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The Cog Railway is still running (3 seasons). - Probably always will. It's a historical landmark. |
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Okay, so even if they DID work in the water, I HIGHLY doubt they could produce enough heat to matter. Basal metabolism for an average human (no exercise, basically) is 60-90 kcal per hour, which ramps up to 300-400 kcal per hour when shivering. Assuming that this device would be even remotely as effective as the human body's own survival techniques, it would need to give to you... say 150 kcal per hour. If I did my math right, that is equivalent to 1.3 kBTUs or about 4 100-watt light bulbs, whose energy is going directly to the survivor. That's a lot of heat, not even counting how much is lost as not ALL of the heat produced by the device will aid the survivor. |
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Furthermore, the HUGE problem with just warming the neck, face, hands, and/or feet is doing so 'tricks' the body into thinking that it's warm when it's not. Just like drinking alcohol before going outside doesn't really keep you warm, you just FEEL warm. It has been shown in clinical studies that heating those parts of the body exclusively actually causes a DROP in body temperature, as the body's thermoregulation systems think that they are doing their job when they're not. |
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Wet/dry suits or survival suits, which work on the basis of passive insulation instead of active heating, are what the US Costguard uses, so I'd stick with that. |
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Good thought, but totally impractical. |
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So we use a 400 watt heater? No problem, jus string the heating elements around the body, power by a battery... and all the salt water electrocutes your victim. |
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Or we just use the heating devices that produce a rapid oxidation by using the water available. Iron filings and salt... which are very heavy... |
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I'm thinking the passive heat barrier is starting to look pretty good. It's not very dense, so it helps to buoy up the body, and it will improve the efficiency of any heating devices we can add. |
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I'm also thinking that we need some lighter than water heating devices, and since heat rises, we shoud put them on the legs, and buttock region of the person, where the heat will then seep upwards on the body, and in the water around them. |
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[+] I'm suprised these aren't already available. |
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