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."

Comments

Re:A personal airconditioner?

[dvoecks]

That only works if the air temp is lower than 98.6. This sort of thing works by harnessing the difference in energy between the "hot" side and the "cold" side. Sure, it would work well at room-temperature, but who needs cooling at room-temp? About the only time you really need cooling when the air is significantly below normal body temperature outside is when you've got a fever, or are heavily exerting yourself. I definitely could get behind a headband that powers an mp3 player when I'm on a jog. It could have military applications, but it would be fairly limited. When it's 120 degrees in Iraq, this thing wouldn't work even if the soldier was running a marathon while dragging a broken down Humvee.

Re:A personal airconditioner?

[Thelasko]

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?

This also defies the laws of thermodynamics. Allow me to explain:

1. In Iraq, the surroundings are hotter than the human body. Therefore, it is impossible to harvest energy from human waste heat because heat is flowing to the human, not away from it.

2. The temperature gradient between a humans body and it's surroundings is not large enough to generate significant amounts of electricity. If it was, internal combustion engines would be a hell of a lot more efficient than they are today.

3. If the temperature gradient between a human body and it's surroundings were large enough to generate significant amounts of electricity, you might want that energy to keep warm!