On Aug 9, 8:02 pm, .p.jm@see_my_sig_for_address.com wrote in
Think of this - stand next to a campfire on a cold night. up
> close = toasty warm. 10 feet away = cold.
The overwhelming majority of heat emitted from a fire, is convective heat, not radiant heat. There is some radiant heat but it is very small compared to the convective heat.
That is radiant heat in
> action.
> The power falls off as the square of the distance. "radiant
> cooling', if there were such a thing ( there is not, just as there is
> no such thing as 'cold', there is only 'absence of heat' ) would work
> exactly the same.
Um, the human body can give of heat via radiation as well as conduction and convection. If you put your hand near a piece of extremely cold metal, you'll feel a perceptible amount of cold even if you don't touch the metal. This is an example of radiant cooling. There is a sharp difference in temperature between your hand and the cold metal. Physics wants to equalize the temperature and will attempt in whatever way possible to do so. If you are not touching the metal [a painful conductive cooling], then the next option to equalize the temperature is for your hand to emit IR radiation and warm the metal. In this case, your hand is the thermal radiator. Your hand emits radiant heat toward the cold metal.
To your hand, this is radiant cooling. For the cold metal, it is an example of radiant heating, because the IR radiation from your hand will warm up the metal.
And when you heat a house, you do NOT want 'dry air'.
Why not? What's wrong with dry convective heating?
Even
> if you could have it, which you can't.
What makes hot dry air impossible?