About | Blog | Forums | People | Free Newsletter
Trailspace is a product review site for outdoor enthusiasts. Use it to find and share great gear.

Suggestions for a light weight emergancy system

6:19 p.m. on May 1, 2006 (EDT)
(Guest)

Hello, I am part of a university design team asked to do a case study on the feasability of a light weight emergancy system that utilises wind energy to generate electricity. It is intended for climbers caught in extreme weather and supposed to provide heat/light in order to avoid hypothermia or dehydration (melt ice).
We intend to design a vertical wind turbine that can catch the wind from any direction and we would like to get some suggestions from you, as climbers, on what you think are the most crucial criteria the emergancy system should fulfill.
We welcome any thoughts you might have.
Many thanks, Tobi

12:35 a.m. on May 2, 2006 (EDT)
MODERATOR
38 reviewer rep
1,741 forum posts

I don't profess to be an expert climber, but in my limited experience, what you are proposing just doesn't seem feasible for a lot of reasons.

Consider the following:
It takes a lot of heat to melt snow and a liquid fueled stove such as an MSR XGK is the standard. I have one and it is very efficient at doing that. Gas canister stoves tend to not work in very cold weather, but are also very common. It would seem to me that you would be hard pressed to generate enough electricity to put out the same energy you can get with something like white gas to melt snow. A comparison of the output in BTUs of a stove like an XGK with some kind of portable heating unit would seem to me to be the first step in determining how much power you need to generate to melt a particular amount of water. Furthermore, unless you expect constant wind, heavy batteries will be needed to store the energy; this alone would discourage anyone from using a unit like you propose.

If the weather really is extreme, then you may have high winds that will necessitate the generator being sturdy enough to withstand the wind-again, this means heavy;

How do you intend to warm someone with a heater? Unless the tent is sealed and insulated, heat loss in extreme weather will prevent a heater from doing much good unless it is something you could fit into a sleeping bag. One alternative would be to use it in a snow cave, which would provide insulation; this presumes you have the time, energy and right place to dig one.

From what I know from a lot of reading and my limited personal experience in bad weather at low altitude, the last place I would want to be in a storm is outside fiddling with some wind generator instead of in my tent tucked into my bag waiting out the weather. Taking off a glove to get it set up in subzero weather would also be an invitation to lose a few fingers to frostbite.

This idea might work at a base camp supported by a big crew of Sherpas or where the base camp gear has been brought in by ski plane or perhaps by sled, but it would a heck of a lot easier to bring plenty of fuel for stoves and heaters than deal with a generator and batteries.

I know there are several experienced climbers who post here so I hope they add their comments and bring their experience to bear on this idea. I'm sure they will have other thoughts on this that I have missed.

9:08 a.m. on May 2, 2006 (EDT)
TRAILSPACE STAFF
234 reviewer rep
924 forum posts

This is actually an idea that's crossed my mind from time to time. As an emergency measure it makes quite a bit of sense: exposure to severe storm conditions is the cause of many high-altitude fatalities, so being able to harness some of a storm's energy (wind) to protect yourself from that storm would turn the equation on its head.

As Tom points out, it takes a lot of energy to melt snow/ice into water. A turbine with that much output may to too big to be practical.

However it should be possible to make a small, lightweight turbine that could generate enough wattage to power a personal heat source -- something along the lines the North Face MET5 Jacket, maybe.

Now that I think about it, you could probably melt snow, slowly but effectively, if you made the heater in the form of an insulated water bottle cozy, with the heating element on the inner surface. Slide in a bottle, let it warm for an hour or so and you might come out of it with some water.

The turbine itself should be easy to mount in a variety of positions and locations: tent poles, the shaft or head of an ice axe or ski pole, even the top of a backpack while on the move. It should be self-cleaning, or at least not prone to freezing or clogging with snow or rime. It should include a backup system to avoid loss: a loop to clip in a carabiner would do. Don't scrimp on the wiring or connectors: they must be able to handle serious abuse.

12:56 p.m. on May 2, 2006 (EDT)
TOP 10 REVIEWER REVIEW CORPS
2,249 reviewer rep
5,186 forum posts

Having spent a bit of time in storm situations on Denali and other peaks, I have to reinforce some of Tom and Dave's comments and add a few others.

First thing is to determine what you mean by "extreme conditions." I have spent a lot of time on mountains where wind speeds exceeded 50 knots, and some above 70 knots (these were measured with a pocket weather station, a Kestrel 4000, on several North American mountains, including Denali, plus measurements from a nearby weather installation the rangers on Denali had at 14,000 and 17,000 ft). I have also encountered winds in the 50 knot range during winter trips in lower 48 mountain ranges, including 60 knots according to the meter at the weather observatory on Mt Washington. This places a constraint on your wind generator that it has to be able to withstand winds of that level for sustained periods, while generating the required electric energy. In the Alaska Range and in winter in various of the western US mountains, plus the Presidentials, temperatures can frequently range doen to the -40 deg range. This places a temperature durability constraint (the gear must operate at such temperatures or even lower), plus the energy output must be sufficient if the windspeed is only a 5-10 knot breeze to still provide the needed heating.

If climbers are going to carry this unit, it must be extremely light weight and compact. Otherwise, it will just be too much weight to add to an already too-heavy pack. In addition, It must be easy and quick to set up, while still being durable enough to withstand the wind and temperature conditions.

As Tom noted, it may be necessary to store energy for later use. Electric energy storage devices are still rather low energy density, I suspect, whether the newest battery technologies or other energy storage approaches. Thus you may not be able to meet weight constraints in storing the energy and have to be content with real-time generation, which puts a major constraint on the minimum efficiency of conversion of wind to electric energy.

Here are several bits of data you need:

wind energy density as a function of wind speed and altitude

efficiency of conversion - (1) the wind machine itself (Darius machines are not particularly efficient, nor are some of the other vertical machines, although the Darius-type could conceivably fold up compactly); (2) efficiency of the generator itself (do you need a permanent magnet to "prime", or can you use a small battery to prime e-m coils?). Keep in mind that this is a function of wind speed - many present wind generators have maximum allowable wind speeds. (3) efficiency of conversion of electric energy to heat (this is a very weak spot for electric heating)

structural requirements - material strength of the generator assembly itself, including the rotor; bracing/guying to support the device in strong winds; anchoring (can you anchor in snow or ice, or loose rock rubble, or more solid rock - can't drill bolt holes during an emergency situation.

cost constraints - it will have to be cheap enough as well

Dave and Tom noted a couple ways to reduce the amount of electric energy needed - heat only the sleeping bag, or a thermal suit (the TNF one Dave mentioned, or something similar to NASA or military pilot electric longjohns). There are electric socks and gloves that run off C or AA cells, which could be used as a basis for figuring the conversion efficiency and output rates.

Melting snow or ice for water is a high demand. Remember that it takes 80 kcal/liter of water derived from ice, IF the ice is at 0C. Problem is that on high mountains that are already at low temperatures, the ice would have to be heated up to 0C, and you have a lot of loss to the surroundings, unless you put the ice in an insulated container, so that the heat does not escape as fast as you melt the ice. Then you need to heat the water to a usable temperature (you lose body heat when drinking water colder than body temperature, not a good thing in an emergency situation), at 1 kcal/deg C/liter.

Tough problem. But, hey, it's just an engineering problem. And what do I know? I'm just a scientist (theoretician, at that) who has wandered around the hills for a couple years. (sign above the work station of one of our top-notch technicians where I worked before retirement - "A scientist is an engineer who can't design anything. An engineer is a technician who can't build anything.")

6:12 p.m. on May 3, 2006 (EDT)
36 reviewer rep
1 forum posts

Here's a few suggestions:

I fly r/c electrics with Lithium batteries and get 20-30 mins on 2- 1.2mah batts- 7.4V- 2oz( drawing 3-5 amps) then add another cell thats 11.1V- 3oz. So theirs your storage units, would fit nicely in the lining of a jacket. They make 2.1, 3.0 and 4.2 milliamp packs too. Important point- lipo's charged = 8.2-8.4v( 2 cell) and 12.6v( 3 cell)

As far as wind power, use 2 -3 layered ripstop nylon with carbon rods as a wind mill hooked up to a small generator( in the 70's I had a bike w/ a silver generator)

Best of Luck

Mike

6:30 p.m. on May 3, 2006 (EDT)
(Guest)

Great comments. I think the considerations already mentioned are worth merit but I love the idea and would be interested in taking a look at your finished product. I will say that in the age of gadgets alternative energy for any reason is a good thing to pursue. Many carry cell phones that go dead, portable laptops, gps, PLB's all of these are instruments that can be handy in a survival situation and need power. Portable solar panels are not always available and with a length of cord one could easily stay out of the elements and still take advantage of power generated by wind. This is handy for a whole host of issues from survival & tactical situations to research at remote workstations. Give me a heads up when you work up your prototype and I will have a look at it. www.RangerMade.US

8:57 p.m. on May 4, 2006 (EDT)
22 reviewer rep
5 forum posts

OK--I'm not a climber, I'm a caver. That said, I'm also an engineer.

To be effective, your wind turbine would have to be much heavier than would be feasible to carry up a mountain, even if you could break it up in modules that each person in the party could carry. For emergencies, you're better off with something that either preserves heat (tent, clothing, sleeping bag), or generates heat directly from a energy dense source (campstove, food).

As others have noted, there exist small, light, collapsable solar panels big enough to recharge a radio or cell phone. That might be useful in the right circumstances.

6:54 a.m. on May 6, 2006 (EDT)
(Guest)

Sounds like a great idea, but as a lot of people have pointed out it would have to be a tough one to make work. The weight/strength thing is the big issue. For alpine climbing or any long backcountry stuff it's just got to weigh almost nothing...yet be incredibly strong to work in the conditions that you're talking about. 100-200kph winds (50-100mph??) are quite possible.

Instead of a device that is a one-stop emergency power source, what about something smaller/simpler that only puts out enough to charge a small electronic device (eg satphone). A couple of people have suggested that a solar panel is more useful than a wind generator, but there's places in the world where there's often a severe shortage of sun but never a shortage of wind (eg New Zealand).

11:25 a.m. on May 9, 2006 (EDT)
TOP 10 REVIEWER REVIEW CORPS
2,249 reviewer rep
5,186 forum posts
Best approach - prepare and train, so you don't have an emergency in the first place

There is one major problem with the emergency system that no one (including me) has yet mentioned. And that is, the best emergency system is training and preparation. With all the wonderful widgets that are now available, far too many people are heading out with the assumption that their array of electronics is going to save them. There have already been far too many cases of people calling in on their cell phones, giving their coordinates as read from their GPSR, and demanding a helicopter pickup, when they were within a hundred yards of a trail that would lead them back to their car. And the other extreme, getting out there dependent on the devices and (1) not knowing the basics of how to use them and/or (2) having the batteries die, or dropping it on a rock or into a stream, and having it become unusable and/or (3) expecting their cell phone to have coverage in a wilderness area. This winter brought out a number of cases of people hopping on a snowmobile and heading into the woods, only to trigger an avalanche or get lost or have the machine break down (no snowshoes or skis along, of course, and a couple days hike in summer even if there had been a good trail).

While I think it might be ok for an experienced team to have something of the sort you propose (assuming the engineering problems could be overcome), I fear that this might turn out to be yet another crutch for the unprepared and inexperienced. Yes, even the best-prepared and most experienced can get blind-sided (I just read "The Last Season", which recounts how one of the best backcountry rangers in the Sierra died, with his body being undiscovered for several years). But somehow, the hubris of too many people who set out into the wilds depending on their array of technology needs to be avoided, not encouraged by adding yet another magic device. No, I am not a Luddite (my fellow LNT instructors sometimes call me "Dr. Gadget"). I just believe, after years of bailing out too many people too far from civilization, that ya gotta know the basics and ya gotta prepare and think things through beforehand. Don't depend on the technology. What do you do when it all goes south?

11:29 a.m. on May 9, 2006 (EDT)
TOP 10 REVIEWER REVIEW CORPS
2,249 reviewer rep
5,186 forum posts
Re: Best approach - prepare and train, so you don't have an emergency in the first place

And before anyone says "get a satphone" or PLB or EPIRB, those can fail as well, and they also won't get help to you in 5 minutes like calling 911. (I worked on one of the major satphone systems when it was being developed some years ago, and it's great that you want to use it - helps provide dividends to support my widget-addiction and retirement. But don't say I didn't warn you that it can and will fail at critical moments).

8:33 a.m. on May 21, 2006 (EDT)
(Guest)

Thank you all for your detailed responses. If we are allowed to then we will post some of the results of our efforts for you to look at and scrutinise.

April 19, 2014
Quick Reply

Please sign in to reply

 
More Topics
This forum: Older: FAQ section Newer: Why you climb?
All forums: Older: Sleeping Pads Newer: Boot inserts