In my last column,
I began describing radiation heat transfer and the factors affecting
it. Radiation is a more complex phenomenon than it appears at first
glance, so it's necessary to carry on the discussion to give you a
complete picture of what it is and how it behaves.
To recap my last column, radiation is energy transfer via electromagnetic waves. It does not release its energy until it falls on a surface or passes through it. Then it's converted into heat. For heating purposes, infrared radiation is the most useful, and most commercial radiant heating devices operate in the infrared range.