Radiant heat production (CAUTION: physics may be involved)

[Waramanga]

I am sure that this will be an easy Question for someone to answer.....I can be the first engineer to have wondered.....

Can you produce radiant heat by any other means apart from heating an object? My current understanding from looking at my heat transfer books is that the temperature (relative to its suroundings) of the object is the variable that determines the amount of radiant heat it can transfer.

Also, is there a way of improving the efficiency of a radiant heater such that it radiates in the right frequency bands? I know that you can get a selective surface that absorbs energy bands more efectively than others so I guess that the reverse may be possible.

I am trying to calculate how much 'radiant' heat is emmited by a hot water panel 'radiator'. I get the feeling that the name radiator just indicates that it gets rid of heat rather than the mode by which it gets rid of it.

thanks for the help (any links etc appreciated too)

 

[IRstuff]

There are quantum cascade and other lasers that put out infrared energy.

Emission is a function of emissivity, surface area, view factor, and temperature. Black in all bands is better.

Anything that radiates in a fluid atmosphere, be it air or liquid, also convects.

see:

http://en.wikipedia.org/wiki/Heat_transfer

to start

http://en.wikipedia.org/wiki/Convection

http://en.wikipedia.org/wiki/Planck's_law

Online HT text

http://web.mit.edu/lienhard/

http://www/ahtt.html

TTFN

FAQ731-376