Wearable Cooling

[acr[]mion]

I'm currently working on my final design project at uni - designing a wearable cooling device for very humid conditions (e.g crowded rock concert), which would be worn on the wrist. I'm proposing to use an umbilical system, which means (from what I ..umm.. researched) that i need a reservoir, pump, cooling device, heat sink, power source... From what I understand, the temperature of the device needs to be kept above the dew point to

minimise condensation. My challenge is to somehow fit all that inside a wrist band/cuff and to use a motor (Wellington Motors - they are special) somewhere in the device. The other option that I have is using a series of inbuilt Sunon mini-fans (8mm square). Being a design student, I have a very limited knowledge of the issues involved. And since my

understanding of practical issues regarding physics is severely underdeveloped, I was wondering if anyone could provide me with some advice.

[YT2095]

fans will only cool to the ambient air temp, although great for removing heat in excess of this, it isn`t really active cooling. and for the amount of heat you wish to disperse I fear you`ll need something larger than just a wrist mounted device.

 

a refrigerant like SO2 or NH3 or some CFCs in a flexible silicone tubing running through a suit with a small compressor and heat exchange would work, but the power requirements would be considerable.

 

it looks like you`ve really set yourself a difficult task! Good Luck

[acr[]mion]

CFCs eh.... I'd have to commit myself to a lifetime of tree hugging to make amends

[drz]

I had always considered just using little co2 cartridges for pellet guns. Using some flexible rubber tube, with vents in key locations.

 

The cartridge (s) could be contained in a little holder, and a release valve could be rigged (perhaps from an old pellet gun) to blast squirts of cold air through the system.

 

I have no idea how much cooling one cartridge would give you, but it is the easiest, least power consuming method.

[5614]

shooting air at yourself would produce similar results to using a fan.

 

i think a way to get this to work would be to use a material which conducts heat well, this would allow heat to be conducted away from your body.

 

you also want a material which does not trap little air pockets, as it is these air pockets which keep you warm in clothes.

[Phi for All]

Does it have to be the wrist? Is that so you can direct the fan where you need it? I ask becaue you might be able to use a bit of psychology in your design as well.

 

It wouldn't be necessary to provide as much cooling if you provide an illusion of cooling where most people would feel the difference--on their head or face. Think about it; if you're sweating at a concert, where are you going to be most conscious of it, on your arm, your chest or on your face? In fact you'd probably use your arm to wipe the sweat from your face.

 

If you had something people could wear around their necks that would cool the head and face and not look too weird, you might not need to cool the body.

[5614]

but that brings on the problems of looks, cool the wrist, cools the blood passing through the wrist, that blood goes along and cools the rest of the body.

 

the best coolant is cold water [for household items,] because it:

 

1) conducts the heat of you better than the air does

2) it feels cold [physcological]

3) it cools the blood, which as it circulates the body, cools the rest of the body

[Phi for All]

Make the water too cold and you've got condensation making you look worse than if you'd just sweat it out.

 

What if you use the water in conjunction with the fan as an evaporative cooler? Circulate the water slowly across a mesh and blow air through that onto the arms to cool the blood?

[5614]

you have to think of this as a suit, not a bunch of fan and water squirters all over your body!

 

sweat might not look nice, but is very good at reducing the heat in your body, as is water.

 

as a cooling down mechanism fans are good, but as a cooling in general system, fans only make you fell cooler, they dont actually cool your temeperature down.

 

if you are wet and blow air on you, that cools you down even quicker, as the water speeds up the conduction of cold air.

 

remember air is a very poor conductor of heat, [whilsts obviously heat travels through air]. 99% of insulation is done by trapping pockets of air, as air is a bad conductor.

[Phi for All]

you have to think of this as a suit,

We went from a wrist cuff to a whole suit?!?

 

but that brings on the problems of looks

sweat might not look nice' date=' but is very good at reducing the heat in your body[/quote']No offense, but you need to decide whether looking cool (pun intended) at a rock concert is important. I think for most people it would rank pretty high. Concerts are very social events, and I think wearing a techno device, no matter how weird, is preferable to being all sweated out.

fans only make you fell cooler' date=' they dont actually cool your temeperature down.[/quote']If you feel cooler, then the device has done its job, whether or not your actual temperature is lower.

 

designing a wearable cooling device for very humid conditions (e.g crowded rock concert), which would be worn on the wrist.

Since this is the limitation, how about a combination device, something that circulates water around the wrists to cool the blood, has fans that cool the water and fans that can direct air at your face (or anywhere else) as well?

 

Takes care of the psychological and the pysiological at the same time. You would probably need one on each wrist and they would need to be at least 4" wide to accomodate all the stuff you're putting in there.

[drz]

the thing about psychological tricks is they work until people realise its just a trick. Its like when I was younger and would get hiccups, my dad would instruct me to fix a glass of water and put a butter knife in the cup, and drink the whole thing without stopping. It worked like a charm everytime I had hiccups.

 

But then when my dad told me the only reason it works is because you think the knife is doing something. From that point on, it has never worked for me again???

 

As to rock concerts, I personally get dirty. I remember Lollapalooza in Raliegh back in 1999. Korn was playing, when we discovered the astro turf grass type stuff comes up it nice lil 1ft square patches. Perfect ammo for the pansies in the seated section. A concert isn't a concert unless there is dirt (and bodies) flying through the air, mud slides, mist tents and overpriced beer.

[Phi for All]

the thing about psychological tricks is they work until people realise its just a trick.

I see what you mean, but air across your face when you're hot and sweaty is going to feel good no matter what your state of mind.

I remember Lollapalooza in Raliegh back in 1999. Korn was playing' date=' when we discovered the astro turf grass type stuff comes up it nice lil 1ft square patches. Perfect ammo for the pansies in the seated section. A concert isn't a concert unless there is dirt (and bodies) flying through the air, mud slides, mist tents and overpriced beer.[/quote']ROTFLOL! But it's the pansies in the seated section who can afford the closer seats and the personal high-tech cooling devices and they are in their best threads for this event!

 

The ultimate concert event: you're in your Gucci threads with your acr[]mion-brand wrist coolers, seated in the second row center $500 seats when WHAM! you get nailed in the back of the head by one square foot of astroturf, frisbeed down at 90mph from the nosebleeds by a dirty, sweat-covered Korn-dog who toasts you with his $6 beer-in-a-cup!

[acr[]mion]

shooting air at yourself would produce similar results to using a fan.

 

i think a way to get this to work would be to use a material which conducts heat well' date=' this would allow heat to be conducted away from your body.

 

you also want a material which does not trap little air pockets, as it is these air pockets which keep you warm in clothes.[/quote']

 

So far in my design i have specified a wicking material to be in contact with the skin. Same stuff they use for athletics wear... But the outside would have to be well insulated to prevent the amibient heat from heating up the coolant..

[acr[]mion]

you have to think of this as a suit' date=' not a bunch of fan and water squirters all over your body!

 

sweat might not look nice, but is very good at reducing the heat in your body, as is water.

 

as a cooling down mechanism fans are good, but as a cooling in general system, fans only make you fell cooler, they dont actually cool your temeperature down.

 

if you are wet and blow air on you, that cools you down even quicker, as the water speeds up the conduction of cold air.

 

remember air is a very poor conductor of heat, [whilsts obviously heat travels through air']. 99% of insulation is done by trapping pockets of air, as air is a bad conductor.

 

 

Sweating is pretty useless though in humid conditions, since the atmosphere is already saturated with moisture, the sweat can't evaporate from the skin surface. Overall humidity affects our perception of the temperature (http://www.coolvest.com/dangers_of_heat_stress.htm)

 

Also, i surveyed a whole lot of 'moshers', and the general concensus is that whatever form the device will take, it has to be unobtrusive (visually and physically) and either concealed or socially acceptable. Most women don't mind it as a fashion accessory, but the guys prefer something less "gay". And no one wants to wear something that is really obvious as a cooling device. Imagine someone in a Korn moshpit with a fan strapped to their wrist... ...hha.. They would gain little sympathy from fellow moshers.

[acr[]mion]

My cooling wrist band also needs to generate its own power, as any external power sources would be too cumbersome. I'm trying to figure out the most effective type of motion that would activate the generator....

[5614]

having a magnet inside a coil produces current, when the magnet is moving.

 

however this would be a large solution and it would be easier just to use a few button or cell batteries [the little flat round ones] as these would easily fit into your design.

[YT2095]

oh good greif, I can`t beleive where this thread is heading, but it`s looking like the pseudoscience section already

 

give GOOD Science, or say nothing to the guy, you`re NOT helping him!

[Vicious101]

hmm well shaper image made these cool looking cooling bands that go on the back of your neck you might wnat to look into those but im not sure how they cooled it looked like a gell and they run off like AA batterys

 

as for water cooling pc's have presure water cooling systems why not make in smaller? its not like your trying to cool a pc with it now

 

like rig the presure cooling system to something that can retain a cooler temp for a long poirod of time then just have the water system pump cold water tubes over the "something" thus cooling it down thus cooling you down and since it retains cooling you wont need to have it run at a higher power level thus reduceing the power cost on it

 

but im not sure how much power is needed to run a water presure system so BAH!

[acr[]mion]

oh good greif' date=' I can`t beleive where this thread is heading, but it`s looking like the pseudoscience section already

 

give GOOD Science, or say nothing to the guy, you`re NOT helping him! [/quote']

 

 

Heh.... I'm not a guy. But I wish I was, so thanks

[acr[]mion]

With regards to power generation, I am proposing to use kinetic energy. I'm in the process of trying to figure out the range of movements that the device would be exposed to. ....Oscillating? Centrifugal? ...Bahhh.... I find the logistics of it all perplexing. Expired bacon knows more about generators than I do.

[Dudde]

well that's good, we NEED more girls around this place.

 

did you also happen to ask those "moshers" where they think the best place to hide something like that would be? Or you did, and they just weren't sure; they just knew they didn't want anyone else to see it?

[acr[]mion]

well that's good' date=' we NEED more girls around this place.

 

did you also happen to ask those "moshers" where they think the best place to hide something like that would be? Or you did, and they just weren't sure; they just knew they didn't want anyone else to see it?[/quote']

 

 

Considering that people don't tend to wear layers of baggy clothing in moshpits (unless it's eminem, etc maybe?), especially some girls with little foresight who think they've come to the beach, there is no room for hiding anything. So it needs to be camouflaged, i.e if it's a rock concert, it would, perhaps, look like a studded wrist band. No one will wear it if it's obvious - it's as much about image as it is about music.

[acr[]mion]

...And how do I generate power for this thing?... ....As much as I like magic, I have a feeling that it doens't apply in this case...............

[jsatan]

Just thinking about it quickly, first thing is the heat you collect has to be moved, if this system is a recycling of the coolant system then there has to be 2 things to move this heat.

1. Large heat sink (large surface area)

2. Or have the heat in one place (smaller surface area but all that heat in a smaller place)

 

Number one seems out of the question because the surface area of the body if pretty big and isn’t doing a great job (I know they are wearing cloths)

 

So number 2 it is, as for power you are going to need a lot.

 

Or you could find a coolant that evaporates at body temp that doesn’t burn of smell of give off steam lol.

[jsatan]

Found this while I was looking around,

http://shop.store.yahoo.com/sharperimage-best/si731.html