Peltier Wrist Cooler

[EdEarl]

extrememech.com

 

Yes, the image above is exactly what it looks like: a wrist-worn personal Peltier cooler that, by virtue of being dozens of times more effective than air conditioning at making you feel comfortably cool, could save the US (and the rest of the world) millions of dollars in energy costs per year.

 

Will this work, or will there be health issues, such as blood cooled as it passes your wrist being more prone to clot because it is cooler.

Edited April 16, 2014 by EdEarl

[swansont]

It's uglier than Google glass.

 

from the article

As an aside, I can’t help but wonder about the low-level physiological response when you wear Wristify. In hot weather, the human body’s natural cooling method is to pump more blood to your extremities and the capillaries under your skin — in effect, your body turns into a giant heatsink. If your wrist was always a few degrees cooler, I wonder if your circulatory system would permanently alter itself in some way.

 

 

I wonder if they're tested to see if there's any damage done to the body when it's "running hot" because you've fooled it into thinking that you're cooler.

[Endy0816]

I had heard of something along those lines to improve exercise times. Was a different cooling mechanism but same basic concept.

 

I can't recall reading about any follow-up, not sure if it panned out or not.

Edited April 17, 2014 by Endy0816

[John Cuthber]

I see the picture fails to include the car battery needed to supply the power.

I have experienced the discomfort of an over-warm room and also of carrying a car battery.

I know which I prefer.

There's also the fact that people are actually quite good at dealing with excess heat as long as we are kept adequately watered.

I understand that humans are (,at least, among) the sweatiest animals on the planet.

 

Also, that heat sink will run hot enough to burn you if you touch it; be careful if you give someone a hug.

[swansont]

I had heard of something along those lines to improve exercise times. Was a different cooling mechanism but same basic concept.

 

I can't recall reading about any follow-up, not sure if it panned out or not.

 

That actually cooled the body, though — actual heat removal rather than giving the perception of being cool. They are coy about the technical details (frustratingly common for pop-tech articles), but this device can't be doing all that much. If it was plugged into a wall outlet it might remove heat at a few watts, but battery operated and in pulsed mode?

 

A 1m^2 blackbody at 310K in an ambient area at 293K has to radiate over 105W. If you want to lower the temperature to 309K, it only radiates 99W, so that 6+ W you have to remove via some other means. Peltiers are inefficient; at 10% we're talking more that 60W. And this is battery operated and runs all day? No, this device is not actually cooling your body by that much. It's like the splash of water in your face that feels cool but doesn't really cool you down much.

 

And it's ugly.

[Phi for All]

Also, that heat sink will run hot enough to burn you if you touch it; be careful if you give someone a hug.

 

And the person who wears this will need lots of hugs when they see what it does to their laptop as they type!

[Sensei]

Will this work, or will there be health issues, such as blood cooled as it passes your wrist being more prone to clot because it is cooler.

 

In Peltier cooler cooling depends on current flowing through it.

So you could adjust it with potentiometer and have lower/higher temperature if needed.

 

Mine Peltier cooler tec1-04905 has max 5 A, 5.8 V = ~30 W.

So it would require 8 AA batteries to use it to the maximum (4 serial to increase voltage from 1.25 V -> 5 V, 2 rows parallel to increase amperes from 2.5 A -> 5 A).

Their total mass with container would be 220 grams (measured now).

They will work for 2000 seconds (33 mins) or so.

 

Device would have much more sense, if it would be built-in shoes soles.

Cold plate would be taking heat from feet then to Peltier then to radiators.

Nobody would know that your shoes work this way (which addresses swansont's aesthetic feeling).

And there would be enough place for 16 batteries.

But there is still downside- fast discharge at maximum amperage, and mass of shoes >500 grams higher (I like light weight sport shoes. Mine current one have 332 g each. Additional 220 g is 67% more (and mass of radiators is not counted)).

 

ps. When I the first time saw initial post, without reading, I thought so it will be about generating energy from human heat to recharge electronics.

[Bill Angel]

A small fan on an office worker's desk would be a more effective way to achieve a cooling effect. The body gets rid of heat via perspiring, and a small fan would promote evaporative cooling from the skin.

[Phi for All]

A small fan on an office worker's desk would be a more effective way to achieve a cooling effect. The body gets rid of heat via perspiring, and a small fan would promote evaporative cooling from the skin.

 

A fan app for your phone might fool the body like this wristwatch does, and would probably be free.

[Endy0816]

Looking at MIT's article(source) they seem more designed to slightly lower perceived temperature indoors(cooling in pulses), thereby reducing some of the cost of cooling the whole building. Makes more sense, definitely not an AC replacement like some of these sites are claiming.

 

Peltiers do suck on efficiency. They can heat, they can cool, they can produce electricity; only thing they can't do is be efficient about it. :'(

 

Maybe take several multiple smaller coolers and have them jointed together. Wouldn't look quite so blocky and could pass for trendy/fashionable. Otherwise, yeah, foot would definitely work better. People are already used to foot warmers, this would be a foot cooler. Preferably with a plug, more efficient and would keep people from expecting them to perform miracles.

Edited April 17, 2014 by Endy0816

[arc]

 

In Peltier cooler cooling depends on current flowing through it.

So you could adjust it with potentiometer and have lower/higher temperature if needed.

 

Mine Peltier cooler tec1-04905 has max 5 A, 5.8 V = ~30 W.

So it would require 8 AA batteries to use it to the maximum (4 serial to increase voltage from 1.25 V -> 5 V, 2 rows parallel to increase amperes from 2.5 A -> 5 A).

Their total mass with container would be 220 grams (measured now).

They will work for 2000 seconds (33 mins) or so.

That all seems rather complicated compared to a ziploc bag with some ice in it, or even an old fashioned (Hot) water bottle filled with ice water to cool whatever part of your body you want to associate it with.

[hoola]

the peltier cooler puts more heat into the ambient air than it cools you....like having an air conditioner sitting on a table and not in a window...you feel slightly cooler right in front of it, but everyone else gets hotter....plus it is a waste of energy unless the efficiency is brought way up and it can be functioned with solar or thermionic cells. On the bright side, I don't think it would hurt our own cooling systems, even if used alot...no more than putting your wrist into cold water....that seems pretty innocuous.....