It is I, that autist with the cooling vest, and I have returned with another one of my projects which I briefly touched on in the previous thread.
A peltier cooled vacuum gauntlet.
At the moment I'm still nailing down the concept, but here's what's on the whiteboard at the moment.
Here's the earlier concept I posted in the last thread.
And some rough electrical diagrams.
I have a friend with a CNC milling machine which I can use for the aluminum blocks. Likely it will be controlled by ardurino.
The physical parts will be constructed first and tested with external power/control before I attempt to build the portable power and control circuitry.
>>962807
I wasn't in the old thread but imho the fans look a little silly, mind telling me why someone would actually require such a device?
I think it would be of use if you could measure the entire body temperature and it automatically adjusts the temperature for the hands, for example if you get cold hands because you are anxious of an exam or something like that it would warm them up?!
>>962816
Basically it cools the whole body just by cooling the wrist. Normally vasoconstriction would reduce blood flow to the surface capillaries and prevent you from doing this, but the vacuum keeps the capillaries open.
Imagine it's 110F. You slip on this gauntlet, bam, you feel like you're in a cold room, even if you're wearing heavy clothes over the rest of your body.
The idea is largely taken from here: http://www.slate.com/articles/technology/future_tense/2012/09/avacore_technologies_magic_cooling_glove_from_stanford_won_t_transform_your_workout_.html
This concept has applications for people who have to wear heavy protective clothing in hot environments (HAZMAT, welding, ect.), for athletes, and for people like myself who suffer from medical conditions that make it difficult to tolerate the heat.
>>962819
Currently a whole vest and backpack is required to provide cooling (unless it's just an ice vest).
This device, if I can make it work adequately, would reduce the size and bulk considerably, and allow the use of both hands while the device is active.
The thing which will make my device different is hopefully the greater efficiency with which the cooling is being applied to the body. Drawing heat from the body in this way should allow the body to be cooled without wasting as much power cooling the surrounding air or liquid.
This may even have military applications.
http://hackaday.com/2008/09/27/peltier-based-coolingheating-backbapr/
>>962822
Do you have a proof of concept or is this currently theoretical?
Also what's your patent status?
will i be able to use this outside when i talk to people so my hands don't get all clammy from social anxiety?
how much will the final model cost?
>>962836
I have no patent and at the moment I have no intention of getting one. If one of you steals my idea, then I'll be happy that my idea was actually worth stealing (and happy that I can buy one, I really want this to exist). I'm not in the US anyway, so even if I did have a patent you could still steal it (I think).
The second reason I'm not seeking a patent is because my design relies on what I think is patented technology; I'm not a patent lawyer so I don't really know how that works.
I don't yet have a proof of concept, this is still on the drawing board, but the plan is to have a proof of concept by the end of the month. I have most of the components ready to go and started running tests with the peltier element today.
Designing and fabricating the heat sinks will take the most time, but achieving a good vacuum seal is where I predict the most difficulty. I may end up having to add a glove to the design.
>>962839
This is kinda the opposite thing - it cools you down. Heating would be much easier, but I suspect that social anxiety would not be helped by wearing a gauntlet in public.
A USB heating pad attached to a USB power supply would suffice for heating, but you'd have to do some tests to determine weather heating the wrists affects hand clamminess in any significant way.
Pretty stoopid. They already have these.
>>962857
Link?
Quick and dirty test to see how things go.
Hammered the stock cold heatsink flat so it could press against my wrist, duct taped peltier setup to wrist with a temperature probe between cold side and skin.
Voltage was kept at or below 5V to ensure the element didn't burn (no fan was applied), and to avoid the risk of frostbite.
At 5V the element consumes approximately 7.5W, about 13% of it's maximum rated draw.
>>962883
Other view. Not very good contact, obviously, but we should still be able to get an idea of how things are working.
>>962884
I reduced the voltage when the temperature dropped below 22.0C, and increased it when the temperature started to rise again.
The temperature stayed stable with the voltage at 4.5V. The element drew [email protected], giving us a power draw of ~5.2W. I continued the test for approximately five minutes and there was no real discomfort, although it did feel cold. (room temp is only 24C today).
I take these results to mean that with the contact area afforded by the improvised heatsink can apply 5.2W of cooling to the body with an interface temperature of 22.0C.
A colder interface temperature could theoretically provide more cooling, but may cause more vasoconstriction and end up being counterproductive.
In the full prototype a vacuum chamber will allow a colder interface temperature and a custom built heatsink will give much greater surface area and contact.
The hot side heatsink temperature was measured with a IR thermometer and remained between 36 - 38C throughout the experiment, which is well within tolerance.
After removing the device the skin underneath the heatsink was cold to the touch, and slightly numb, but this resolved itself quickly.
>>962889
I think there's a fundamental flaw in your idea as a whole.
If you're tricking the body into feeling cooler, you're blocking the proper physiological response to the situation.
You mentioned above, (>>962819) the possible implementations of the technology and how it works by reducing blood flow to surface capillaries which is then circulated through the body.
Hypothetically this could work, but all you're doing is creating a cooled blood barrier but you're ignoring core temperature rising. Yes, the cooled blood may help at first, but could also lead to organ failure or even heat-stroke that has no warning system.
Imagine feeling a blissful 74F while welding in full leathers in 115F sunlight only to collapse in pain as a blood clot kills off your kidneys or pass out with no warning as your brain over-heats. Your body is not sweating and your skin is cool to the touch, but your organs are burning up as you bake, unaware of whats happening.
I imagine you're trying to use the vascular system to cool the entire body, but the health risked of restricted blood-flow through different movement or other health issues like plaque build up in arteries could make the device significantly dangerous for wide spread use and I think that's why the only applied applications we've seen of such technology is in applied medical therapies in controlled environments.
>>962924
You've misunderstood the purpose of the vacuum. The aim is to INCREASE bloodflow, not reduce it. Reducing surface bloodflow would cause more overheating.
We're not tricking the body into feeling cooler, we are cooling the body. Nothing here is going to make you feel any colder than your core temperature actually is. What it's going to do is cool your core temperature.
There is no 'cold blood barrier'. Your organs are receiving the same blood as everything else in your body. The natural way for your body to cool itself is to pump more blood to the surface blood vessels. My device aids the body's natural evaporative cooling system in cooling that blood, and thus the whole body.
(...I suppose I can almost see how you would come to your line of reasoning if you thought that I was trying to reduce bloodflow?)
Why don't you tape an ice pack to your wrist
>>962936
It would be too cold and cause the capillaries to constrict leading to only local cooling taking place. It would also melt fairly quickly. There are icepack personal cooling solutions but they tend to be in the form of vests.
An icepack on the wrist is a good way to cool someone down if they are already overheating, but the aim here is to prevent that from happening in the first place, and to make the person more comfortable over a longer period of time. The cooling provided with this device will be able to be controlled much more precisely.
>>962807
I would be worried about excessive moisture buildup in the gauntlet and possible skin damage from prolonged use.
>>962948
Hmm. I suppose that could be a concern. I could put a desiccant inside the chamber (not in contact with the skin). Perspiration inside the gauntlet will hopefully be minimal due to the lowered temperature.
Usage time would only be a few hours (2-4) so it shouldn't be too bad. I've certainly worn a damp wetsuit for longer than that.
You could swap which arm it was on as well.
I'll add it to the list of concerns, but it doesn't seem like a dealbreaker. Thanks :)
I like your concept, but I can't help thinking that vacuum is not the way to to. Even if you can avoid vasocontriction, heat is trasmited very slowly in vacuum. Only by radiation. I feel the net result would be negative.
I feel you'll be better off by a cooling fluid circulating, for example on a series of pipes sourrounding your feet. Vasoconstriction may be less because of gravity. And you can hide the device in your shoes
>>962976
It's only a slight partial vacuum, so that doesn't really apply here.
Additionally, we're not cooling the whole inside of the gauntlet (or at least that isn't the primary goal) the cold heatsink is in direct contact with the skin and conducts heat very efficiently. The peltier element is actively pumping heat away from the cold heatsink.
>>962984
*not cooling the air inside the gauntlet
>>962819
Why are you trying to cool capillaries? Areas of larger vessels are sure fire to draw off body heat.
An ice scarf for example would be near main line access. The arm pits, back of knees, and groin are other locations.
I played around with a peltier cooler with a smaller heatsink and the side it was drawing heat to got hot as fuck until eventually both sides were hot as fuck. how ya gonna cool that shit?
>>962884
It should be obvious by now, but you're probably not going to be able to design a metal gauntlet that comfortably sticks to the skin.
>>963132
A smooth, slightly concave piece will be significantly more comfortable than what's pictured.
>>963055
More difficult to apply a vacuum to the back of the neck. Out of all of those locations, the wrist is the only one that wouldn't require some kind of articulation.
>>963062
The wrist has several large blood vessels near the surface, as shown in the diagram.
>>963100
The cooling system (as pictured on the whiteboard) works similar to a blower type graphics card, sucking air through the hot heatsink. I may actually cannibalize an old graphics card for my proof of concept. Neoprene insulation will be placed between the hot an cold heatsinks surrounding the peltier element.
>>963132
I'm going to custom mill an aluminum block so it sits against my skin smoothly. It will be held against the skin with a neoprene band so it won't be held completely rigid.
Instead of the wrist have you thought about doing it over the femoral arteries inthe legs? No articulation there and plenty of blood flow
>>963194
I hadn't really considered that too much, it seems more difficult to ensure good positioning and seals. I might look into it depending on how the wrist mount unit works.
Check this out OP:
http://spectrum.ieee.org/energywise/energy/the-smarter-grid/arpae-funding-personal-climate-control-systems-with-robots-foot-coolers-and-more
ARPA-E's cooling insoles
>>963324
If I really get this to work I guess I could try and submit it for the 2.6 million dollar reward, lol. (I don't know if that's how it works.)
>>963343
Although, they are offering grants...
TAKE THIS SCHITT TO DARPA, GET A PATENT, AND MAKE FAT STAXxXx selling this dude, but don't you risk injuring the capillaries and schitt by forcing them open and schitt? This might work better around the neck where there are arteries.
>>963541
This is positioned directly over the radial and ulnar arteries.
Instead of sealing at the wrists have you thought of using suction cups instead? If you put conductive material in it you could use them for cooling and suction. I think you're going to have a hard time creating a seal at the wrists.
http://news.stanford.edu/news/2012/august/cooling-glove-research-082912.html
2 late
>>962807
Dr Freeze/10
Your wife is gone, it's time to move on
>>963772
Similar, but not the same.
I don't think you can transfer heat quickly enough through such a small surface area to match what the rest of the body is generating or absorbing from environmental conditions. You need a larger contact with the body, IE a vest or suit.
>>962807
you will never achieve a vacuum and even if you did heat transfer would slow
>>964079
>you will never achieve a vacuum and even if you did heat transfer would slow
This technology doesn't require a full vacuum, just 1-2 psi below ambient. If you can seal it properly an aquarium pump could do it.
>>964079
Does no-one here understand heat transfer? Heat transfers slowly -through a vacuum-. If two objects are in contact, the surrounding gas/vacuum is almost irrelevant since heat transfer is occurring by conduction, not radiation or convection.
alright haven't read most of the thread but op seems to know what he's doing
my suggestions are use a thin flexible conductor as the primary interface with the skin, then behind it run heat transfer pipes and use some sort of state change cooling like a fridge rather than using fans
>>964340
that is way more complicated than heatsink/peltier/heatsink
>>964340
OP here - I couldn't find a small enough compressor to fit a phase change cooling system on my wrist - the cooling isn't actually coming from the fans, but from a thermo-electric cooler. The fans are just to cool the TEC's heatsink. Granted this does cause problems with power consumption, but miniaturization is the main goal with this project.
Heat pipes would be great (to put the heatsink on the top of the gauntlet, but they're difficult for me to manufacture so I'd have to get quite lucky to find some that happen to be the right shape.
What would you suggest as a flexible conductor for the skin interface? At the moment the plan is to use a shaped aluminum block held against the skin with a neoprene strap.
>>964356
I want to say some sort of metal foil. Maybe lay out a dense grid of metal wire then seal it in flexible plastic? Give me some time to look for something more suitable
>>964359
My concern is that an interface that was thin enough to be flexible wouldn't be thick enough to conduct heat effectively, it might be worth some testing.
>>964365
Alright, found you a couple of things. First is CoolPoly which is a thermally conductive elastomer. Second is Graphite Fibre Thermal Straps.
alternately, just use a mobile gas interface instead of a solid contact. blow cool air across the wrist. It'll couple naturally with the body's sweat too
>>964366
or use lots of fine aluminium powder sealed in a flexible plastic perhaps
>>964370
How about a wristband made braided copper wires?
You need to be looking at a liquid cooled system.
>>964372
could also work provided the wires were thin enough
>>964366
If I can source some of those thermal straps I could do something like this, that would greatly increase my surface area.
>>964374
Liquid cooled in what way? It seems silly to add a liquid cooling loop just to move heat a few centimeters.
If I was making a split system then I could run water lines from a belt/back pack to the gauntlet, but at that point a vest would be more practical.
>>964175
I haven't got the drysuit seals yet, so I'm using some rubber gloves to test the fit - it needs to be slightly shorter, my forearm is wider than I thought.
>>964500
I also haven't figured out my vacuum pump yet, but it seems to hold positive pressure at least.
>>964502
I filled it up halfway with water and sucked out as much of the water as I could with a straw. The negative pressure is actually held better than the positive pressure, since it holds the seal closed.
With the dry suit seals, I don't predict a problem holding a strong enough vacuum, hopefully I won't need the glove either.
>>962819
I know this project well. Good luck op.
>>962857
Perhaps did you miss the title of this board?
>>964526
Alright guys, I know what this looks like. Try to contain your sophomoric impulses.
This seal seems more effective, although I've added an extra layer on top of it now.
>>964539
I want to fuck that glove.
>>962807
LIQUID COOLED SUIT.
>>964539
Working more on the wrist seal.
>>964575
I'm thinking maybe inflatable cuffs might be a good option, the elastic cuffs make it tough to put the gauntlet on.
I'm thinking I'll fabricate then from 0.8mm butyl rubber sheet or tube.
I'm also trying to find a small hand operated vacuum pump and gauge, and some small check valves (for the cuffs and vacuum chamber). Would a brake bleeder kit be appropriate for pulling the vacuum?
In the final model it may or may not end up being replaced with a small peristaltic pump, depending on how it performs in testing. The benefit of the pump would be that it could trigger automatically as the pressure started to rise, and potentially drain condensation if that becomes an issue.
>>964678
This is roughly what I'm thinking for the cuffs.
>>964678
Maybe the inner tube of a bycicle tire can function as a inflatable cuff.
>>964688
How do I make the inner tube the right size? Cut and reseal with rubber cement?
>>964688
Like this?
>>964696
Slight modification.
Okay OP I hit the archives and have read through everything you've posted. I have a few suggestions but no real solution I am afraid.
1) I think you should put Mylar sheets on the outside of your cooling vest. There are only 3 ways heat is transferred: Conduction, Convection, and Radiation. Mylar would stop the lose through radiation and should go on the outside to keep the sun from stealing your coolness. That's why heat suits are made of it.
2) If you go the route of a liquid cooled vest I'd suggest copper pipes. You could solder hose barbs on the ends and connect them with vinyl tubing. This way you can have a bunch of short runs (of copper) that is somewhat flexible. Get a round stump and a hammer so that you can shape them to the curve of your back and flatten them out to get more surface area. Use bigger pipe like 3 or 4 cm. Lean back in a chair to get full contact.
3) I worry about about your vacuum chamber idea. I understand that it is a very low amount and you need this to open up the capillaries. However, how do you plan to combat the swelling and get the wrist cooler back off again? I watched an episode of Mythbusters where they were testing to see if alcohol really made a person warm in freezing conditions. They found out that it does make you feel warmer but kills you faster. In the cold your capillaries shrink to the extremities to keep the core warm. Alcohol causes them to open back up and allow the warm blood to reach hands and feet better. Feels good but kills you quicker. I don't know if you can drink on your medications but it does sound simpler than a vacuum chamber; also you now have an excuse for staying drunk lol
>>965202
4) If I were in your shoes the first thing I'd do is tackle the house itself. In the room with AC, you can place empty cardboard boxes to fill up the empty space of the room. If that is too ghetto then you could just hang up some sheets to section off parts of the house. That way the AC unit doesn’t have to cool as large of an area. You could apply tint to your windows so that you still get light in but not as much. What is the insulation in your house like? Maybe time to get that looked at and updated/ doubled. Lastly, do you have a stove vent? It makes a world of difference. With a hood vent you whole home won't heat up every time you try to feed yourself.
5) I don't know how medical insurance works in your country (I barely understand my own- America) but it may be something to at least attempt. So, in my country if a doctor says YOU HAVE TO HAVE 'X' then your insurance has to pay for it. Get your doctor to say that temperature directly affects your quality of life. Then call up your insurance company and throw a fit until they install some cooling. At the very least you could try to haggle a reimbursement.
The volume your talking about is so small why don't you just use a (no needle) syringe and tube to suck the air out? Yes it's a manual action but it's really minor.
>>965211
Wow, that's actually a really good idea, a 60cc syringe should be enough I think...
>>965273
I only have 20cc syringes on hand, the idea seems to work alright, but 20cc isn't enough to change the pressure significantly.
A 100cc syringe is on the way.
Also a vacuum gauge so I can see what I'm doing.
>>965202
You've raised some good points, and I'll address them once I'm back in front of my computer.
>>965537
I tried making some one way valves, one with a filed down screw and the other with a taped flap. They didn't work well enough. Screw kept falling out. I wish I had some ball bearings.
