Stanford Super-insulated clothing

What a joke!

This must be April 1.

This may do a good job with radiated heat loss, but radiated heat loss is only a small fraction of the human body's overall heat loss.

–B.G.–

This was posted earlier by Alan G. , with This Link.

“This may do a good job with radiated heat loss, but radiated heat loss is only a small fraction of the human body’s overall heat loss.”

When I did some googling I found radiant heat lost often stated as around 60%. I was surprised, but couldn’t sort out the discontinuity.

There are lots of questions about this approach, but the fundamental physics of heat loss should not be one of them.

So, any Science insights about radiant heat loss for a clothed person under open sky?

"So, any Science insights about radiant heat loss for a clothed person under open sky?"

Well, radiant heat loss depends on what you're exchanging radiation with. Heat exchange is proportional to the difference in the two objects' temperatures, each raised to the fourth power. So your radiant heat loss fraction under a clear sky on a warm night will be large; under a cloudy sky on a cold night, smaller. Further, radiant barriers only work if there's a gap between the two surfaces involved (in this case, your skin and the clothes). Where the clothes are touching you, conduction will dominate and the reflectivity will be wasted. Color me skeptical.

I've measured (using crude instrumentation), but more applicable to sleeping

For sleeping, maybe you get 10 degree F of temperature difference due to radiant heat loss. Maybe 50 F due to your bulk insulation, but it depends on how much insulation/loft. Radiant heat loss is a minor effect.

But for clothing, you need a lot less insulation because you generate more heat, so maybe the proportion lost due to radiation would be more.

I think the claim that it radiates heat back to your body is incorrect. It needs an air space to work. Your clothing would have a very small air space between the radiant layer and the next surface closest to your body.

But you would radiate less heat to the air if the radiant layer was on the surface, but if it was windy it wouldn't work nearly so good.

ha! Todd beat me to it : )

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