On Thu, 10 Nov 2011 22:26:19 -0000, Martin Brown wrote:

On 10/11/2011 21:42, Lieutenant Scott wrote:
On Thu, 10 Nov 2011 21:38:58 -0000, Roger Chapman
wrote:

On 10/11/2011 20:30, Lieutenant Scott wrote:

Why are they called radiators when they are primarily convectors?

ISTR that it is roughly even stephen but can't remember whether the
information relates to modern panel radiators or the old fashioned
monster cast iron ones which were the original radiators.

Probably the old ones. You can test yourself, just see how much hot air
is flowing up form the modern ones (there's a reason for that concertina
stuff inside). And you can't feel anywhere near as much being radiated.
Mind you it might help if they were black, but then you'd need brighter
lights,

In the thermal longwave infrared just about anything that isn't a shiny
metallic surface is a good approximation to black - even white paint.

ISTR as a rough rule of thumb radiative heat transfer starts to become
significant at about 55C with an ambient of 20C. It scales with absolute
temperature to the fourth power so takes off rapidly.

My Physics teacher (who had a Doctorate) disagreed. Stupid woman.

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