I read an article [1] years ago about how exercising with a glove that had coolant flowing through it enabled both athletes and regular exercisers to have longer lasting sessions because they could cool down more efficiently.
Since then, I've thought that something like a simple strap for the hand which had a copper plate for the palm and a bunch of heat dispersal fins like on a GPU on back of the hand, with some sort of liquid running through it to help pull out the heat would probably help quite a lot to help cool you down while exercising...
Oh, yeah. they've been working on it for years [1]. You're probably thinking about the same articles I am, from 2012 when all the blogs picked it up as "better than steroids" [2]. I'm with you - I thought they'd have a consumer product out by now. Also, there's some debate about whether this actually works, but I did some personal testing years ago when I had access to a treadmill and was able to jog longer with my hand cooled.
There's a product called Coolshirt that does this. Ice water from a small cooler is circulated through tubes in a vest that you wear.
I heard about them in a motorsport context (race cars typically don't have AC since it adds weight and the compressor uses a significant amount of engine power) but apparently they're marketed to firefighters and industrial workers too:
I remember reading an article years ago (wired?) where someone developed a system to maintain a good body temperature in hot or cold.
I think the end result was a boot that lowered the pressure of the foot, then circulated warm water against it. The person could stay in 32F water indefinitely.
But the article also talked about core body temperature and exercise. High core temperature was a limit on endurance. With a device to keep your core body temperature even, you could basically exercise at high levels for long periods of time.
I don't know why batman doesn't have something like this on his utility belt, especially when he runs around in heavy black clothing on hot sunny days.
> High core temperature was a limit on endurance. With a device to keep your core body temperature even, you could basically exercise at high levels for long periods of time.
Using this cross-disciplinary analysis- clearly, people have bad TIM between the heat-generating components and the IHS (skin). The solution, then, is to either replace folks' visceral fat and so on with liquid metal, or to remove the skin and fat entirely and cool the important parts directly.
Okay, so the comparison might not quite be one-to-one, but...
It depends. The one which fools you would still be useful when it’s warm and uncomfortable but not hot. It’s dangerous if you are overheating and it’s fooling you into thinking you’re okay.
No. What matters is that your body doesn't overheat.
In the absence of devices like the watch, your feeling of being comfortable enough correlates well with your body not overheating. But if you are wearing a device like the watch that fools your body's perception of comfort, you can feel comfortable while your body is actually overheating. That's not good.
> I don't actually want to change my body temperature by 5 degrees, I'd die.
That's not what the patch does. What the patch does is keep your body from getting hotter in an environment where it otherwise would. And you can tell that it's doing that because you still feel comfortable, and the patch isn't fooling your body's perception of comfort, so if you feel comfortable, you're ok.
If you start feeling too cold, you just take the patch off. So you don't need to worry about your body temperature dropping.
At lower temperatures, parts of me get colder than necessary. And there's lots of room for my skin temperature to go up safely that my body is not making use of.
At higher temperatures, I'm already past saturation on evaporation, and the excess just dehydrates me.
> Would it stop you from sweating as much?
Well I sweat less when it's colder. So whatever definition of 'feeling' colder is necessary to cause that effect, that's the definition I choose.
> At lower temperatures, parts of me get colder than necessary.
Then you wouldn't want to wear a device that made you feel even colder, would you?
> At higher temperatures, I'm already past saturation on evaporation, and the excess just dehydrates me.
And making you feel cooler would not change that your body is not actually being cooled--if you're at saturation, your body can't cool itself. So to avoid your body overheating, you would need to go someplace that is actually cooler. Just making you feel cooler wouldn't help. (You might get some increase in the time you could stay outside if your body sweated less and therefore dehydrated less.)
> Then you wouldn't want to wear a device that made you feel even colder, would you?
Yes I would, because five degrees colder than that is still comfortable, but being wet is not comfortable.
> And making you feel cooler would not change that your body is not actually being cooled--if you're at saturation, your body can't cool itself. So to avoid your body overheating, you would need to go someplace that is actually cooler. Just making you feel cooler wouldn't help. (You might get some increase in the time you could stay outside if your body sweated less and therefore dehydrated less.)
I'm not asking the device to magically prevent overheating. I'm saying that the lower amount of sweat wouldn't be a downside, because there would still be enough.
Also I don't actually overheat because I slow down and avoid pushing myself to that point.
This is a tangent anyway, it's the slightly-over-room-temperature situation that I really care about.
A number of cities have a few weeks of 80-100F weather and minimal residential air conditioning. If such temperatures were dangerous overheating, they would need to be evacuated every August. They aren’t. Consensus opinion is to suck it up. If the discomfort has no utility there, why experience it?
> If such temperatures were dangerous overheating, they would need to be evacuated every August.
Oh, so everybody stays out in the hot sun all day? Nobody stays in the shade? Nobody goes indoors? Nobody has houses designed to stay reasonably cool when it's hot out? (There are plenty of ways to do that without A/C.)
If people don't change how long they stay out--just go out for short periods to do something, then go somewhere where they can cool off--I have no objection to them using a device to help them feel more comfortable. But uncoupling your natural perception of your body's condition from the actual state of your body is always risky.
Having cooling be local as possible is exactly what matters. You might argue that a BedJet is silly, but the idea is similar in spirit [0]. The question is: why heat or cool the part of the air that makes contact with things that don't require it? It requires more energy and has costs like creating additional pollution.
I've had random ideas like wearing a wetsuit that regulates the temperature at right at skin-level, so something like this patch is both validation and a marked improvement.
So a flexible peltier? I think peltiers are really interesting, they certainly aren't very efficient, but I'm excited that innovation is happening in that space. Heat pumps without moving parts will always be interesting to me.
Heat pumps are more efficient than a compressor and are more effective than a radiator. You could power it with a solar panel to get power when you need cooling the most.
A compressor is a heat pump. Peltiers are much much less efficient than compressor driven heat pumps. Its why we don't really use them for much, but use compressor a/c and refrigeration for everything.
Interesting, this is a similar idea to whats been used in motorsports for driver cooling systems for a long time. I just got in my new setup from Chillout Systems [1] this week. Since I live in Texas, even many of the club racers like myself invest in these types of systems since it's so hot here during the Summer.
We use to race here in CO (which gets hot but not as hot as Texas admittedly) by dipping our Nomex suits in ice water and racing with ice bags in the suit that leaked so two cooling mechanisms in action. Works for 45 mins. It was great to get out with a completely dry suit after a race. Nothing like cool balls during the race.
I'm not looking forward to them being necessary, but given the news that bits of the world may move past unaugmented survivability, due to wet bulb temp, I have been giving some thought to the cheapest version. So far I have been looking at a solar panelled conical hat, similar to the traditional chinese farmer hats, with a curtain of layers of mosquito net. The layers are seperated and cotain a water condenser that feeds to a storage tube at the bottom that also acts as a weight and a cool environment is kept within the circle under the hat by the air being blown through the condenser.
If you had the cone made of slightly rotated PV strips within a stationary brim and rotated them like a propeller hat you could do convention cooling in an incredibly stylish piece of headgear. X~D
Fantastic idea, you can also then cosplay as a jet engine.
I keep meaning to tidy up my design work for this and stick it online under some sort of open source licence. I'm not sure what the best one is for hardware projects, though the GPL will presumably do.
Having a very large distributed surface area could be key to drive the peltier cells at low current and get back some efficiency. The thermal contact with the body also helps by reducing the temperature gradient against the charges flow.
Anyone have advice on staying cool at night? Now that it’s getting warmer I’m having a hard time sleeping at night. I don’t want to just turn the air down really low since others in my house wouldn’t like it. I don’t want to run a fan all night either. This tech doesn’t really seem to be there yet
sometimes i find even having a ceiling fan on low speed, slightly dries out my eyes overnight/when I wake up in the morning. It may be all in my head, but I seem to remember reading something that your eyes either flicker or don’t always close all the way shut while sleeping. so no fan for me at night ( I just generally keep other AC vents closed a tad so that more pressure comes into my bedroom AC vent and i have thermostat thermostat schedule to be a few degrees lower at night while I sleep, then a few degrees higher around an hour or so before I need to wake up, the heat/warmer temp helps wake me up kind of like an alarm clock )
In my experience I’ve had great results using a buckwheat pillow: it warms very slowly, and the opposite side is pretty much always cool. After a lot of searching for the filling with least/no pesticides and the like sprayed on the buckwheat hulls, I ended up going with L-Oma.com and have been very satisfied.
You can regulate your environment based on the weather. If it's humid, you might benefit from a de-humidifier. If it's dry, evaporative cooling. If the humidity outside is 'average' or 'comfortable', a cross-breeze will help a lot. If it's hotter inside than outside, set up a fan to pump air outside, crack one window from the bottom to let in cool air, and one from the top to let heat escape. As a last ditch measure, you can try filling a hot water bottle with ice water and sleep with your feet on that.
Put it under your pillow rather than your feet. Your brain temperature needs to drop for sleep, and if you cool your extremities the blood will go to your core and make it even harder.
I grew up in New Orleans. My advice is a cold shower before bed, don't sleep under a sheet, being skinny helps too - fat's an insulator. If you've got a lot of that then I suggest, in the most non-judgemental way possible, that you do what you can to change that.
Get a breeze going through the room if you can, open windows in two different walls or something, the air outside may be hot but it's still better to have it moving.
Adjust your air balance to cool your room more. The vents for your A/C have little control flaps to increase/reduce airflow. Open yours all the way up, and slowly reduce the others until everyone is comfortable.
I'm sure it's great for keeping cool in the summer, but there is no way they'll ever work out for cooling buildings. They're fundamentally inefficient due to needing to be built of materials that conduct heat in one direction and insulate in another, while simultaneously conducting electricity and having a large bandgap. Such materials have not been found and are unlikely to exist.
Anyone technical proofing the article should have been aware of that, and should not have allowed such claims to get into the article.
Single phase gas turbine refrigeration can theoretically get to the Carnot efficiency limit, and in reality gets close to it.
You misread the article. They want to save energy by cooling the individual, not the room.
> The use of such devices could reduce the demand for energy to power central air conditioning by 20% in typical buildings, and enhance a wearer’s comfort outdoors, the authors say.
I have embraced a large wet bandana on my forehead / neck / arm / etc. Evaporative cooling for the price of $5 (and the effort of carrying around a bottle of water). Dunno about 10C reduction, but it makes a lot of difference. It also made me question the wisdom of having spent the prior years in unnecessary suffering.
Good point, I was thinking mostly about Las Vegas when I typed that (have to go there every year mid summer).
Well then, another contribution: a few years ago I have found that several months of strenuous cargo exercise made me not care about heat, even the wet heat. I would still sweat and all, but it wouldn't be nearly as bothersome as it was earlier.
The appropriateness of being a sweaty mess makes a big difference. Having a big sweat circle on the back of your shirt in an office is more uncomfortable than being soaked to the bone in your own back yard.
Since then, I've thought that something like a simple strap for the hand which had a copper plate for the palm and a bunch of heat dispersal fins like on a GPU on back of the hand, with some sort of liquid running through it to help pull out the heat would probably help quite a lot to help cool you down while exercising...
1. https://news.stanford.edu/2017/12/27/cooling-glove-helps-ath...