Slashdot Mirror
Body Heat Energy Generation
BuzzSkyline writes "Researchers in Belgium have developed devices to harvest the waste heat our bodies throw off in order to convert it to electricity to run devices such as a wristband blood oxygen sensor and an electrocardiogram shirt. As a side benefit, the power sources help cool you down and keep you looking cool, all while running sundry micropower devices. In fact, the researchers mention that the energy harvesting head band works so well that it can get uncomfortably cold. In that case, they say, 'This problem is solved in exactly the same way as someone solves it on the body level in cold weather: a headgear should be worn on top of the system to limit the heat flow and make it comfortable.' But it would be such a shame to cover up the golden heat-harvesting headband with a hat."
What's next? A body-movement powered (or better, heat & movement hybrid power), fully functional stillsuit?
Colorless green Cthulhu waits dreaming furiously.
You're wasting the real potential of this thing. I live in an area that gets hot as hell in the summer. If it really does get "uncomfortably cold," I'd pay good money for a whole suit made of the stuff.
SJW: Someone who has run out of real oppression, and has to fake it.
It feels cold because it's sucking heat out and using it. So it's constantly leaching heat out. Hence it would feel cold. Simple, really.
Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
If this is true:
Wouldn't it be extremely marketable? Especially for the military with troops in hot places and with bulky body armor and probably all types of personal electronic equipment to keep charged?
As a side benefit, the power sources help cool you down
Typically if you take something that's trying to dump waste heat, and install something that recovers power from that heat, it creates an insulating effect, reducing the cooling the object was receiving. Heat can't be turned directly into energy, only difference in heat. Adding a heat reclamation system doesn't help cool something down because the power it's getting is from the temperature difference, not the heat itself. Instead it takes power from the temperature gradient, and as such reduces the temperature gradient, thus reducing cooling efficiency.
I work for the Department of Redundancy Department.
Those of us who descended from the mammalian evolutionary tree, keep our bodies warmer than ambient temperatures.
FTFA:
"Imagine portable electronics that run on a free, reliable energy source."
Um, I'm already practically there. I can get a KWh out of the wall for 5p (10c), charge up an iPhone from dead to full for a quarter (5KWh battery capacity there) and can get as many cheap chargers as I like. On my list of concerns right now, body-heat chargers are pretty far down.
"I bless every day that I continue to live, for every day is pure profit."
It's better at conducting heat away from your skin than air; and, because it's extracting energy and using a small radiator as a heat sink, it remains colder than the skin. It only feels cold. It would never actually reach ambient because your body is keeping it above ambient, with the asumption that "ambient" is well below body temperature. From the article:
"At 22C, it produces about 30W/cm2, i.e., close to the theoretical limit of power generation on people at this temperature in a compact device. There is, however, a drawback of such high power generation: at lower ambient temperatures, the heat flow rapidly exceeds the sensation of discomfort and the device turns into uncomfortably cold object. For example, at 19C, the TEG already produces 3.7 mW, but the sensation of cold becomes too annoying. "
If your head gets too hot with the hat on, simply put another heat absorber around your hat. If your head gets too cold again, put on another hat.
I was going to just mod you down, but the summary at least never said anything about lowering any part of the device below ambient. It said that the headband will "feel cold". Touch a piece of wood at room temperature. It will sometimes "feel" warm. Do the same thing with a piece of steel. It will "feel" cold. This is true even if both are at the exact same temperature. Heat conduction
The kids section of my local science museum even has hand-shaped pieces of different materials to demonstrate the effect.
The headband is at ambiant temperature, but your body is much warmer. Heat flow from your body to the headband and leaves a cold sensation on your skin. The material of the headband applied to the body is probably a good conductor of heat ; it's like with a piece of metal that feels cold to the touch and a piece of wood that doesn't while both are at room temperature.
I live in Canada... I need all of my body heat as it is.
AccountKiller
It's not sucking heat out, that would actually require extra energy input. It's not a pump, it's more like a water wheel.
But my question has been answered. It doesn't get below ambient temperature. We just don't feel ambient temperature as cold as it actually is, because air is a pretty good insulator.
Give me Classic Slashdot or give me death!
So in warm countries (or during a heat wave), when ambient is *above* body temperature, do yo wear it inside-out ?
What a depressingly stupid machine.
Though perhaps they won't need massive amounts of force to subdue humanity; from what I've seen, most people would choose the blue pill.
I've long believed that the physical reality we live in, being entirely a product of energy and thus little more than an illusion, the idea of matter and as such is inherently linked to consciousness. . , that all things in our reality can be observed as and understood to be metaphors for systems and conflicts we are experiencing in our conscious awareness.
-You have to plug humans into the Matrix at the start of their lives when kids are most inquisitive. Red Smarties are the most popular color, and the battle over Blue Smarties rages on. . !
Humans naturally try to reject the Matrix. "Entire crops were lost."
Neat, huh?
-FL
If you need continuous monitoring, you probably need more accuracy than non-invasive means will get you.
As of 2003 (when I spent a summer internship at Sensys Medical), the best non-invasive method (near-infrared spectroscopy) would get you within 20% of the actual value - and that's with an initial blood sample for calibration. IIRC, most consumer devices are accurate to 10-15%, with cheaper clinical devices being accurate to 5%.
Knowing the hardware necessary for even that degree of accuracy as well as the difficulties we had getting a clean signal while trying to shrink stuff down to shoebox size, there's no way that this would work - not with IR, anyway.
The accuracy should have improved since then, and these numbers are purely from memory. That said, you are right. That would be something - but given accuracy and demand, don't plan on it in your lifetime.
Man, what have you been smoking? I gotta get me some of that stuff!
I've abandoned my search for truth; now I'm just looking for some useful delusions.