All objects are continuely emmiting and absorbing infared radiation
IR is emmited from the surface of an objectIf an object is hotter than it's surroundings then it emits more radiation than it absorbs (as it cools down)
If an object is cooler than it's surrounding then it absorbs more radiation than it emits (as it warms up)
The hotter an object is, the more radiation it radiates in a given time.
ou can feel this radiation if you stand close to something hot
Surface Colour and Texture
DARK, MATT surfaces absorb IR falling on them then LIGHT, SHINY surfaces!
DARK, MATT also emit much more IR (at any given temp)
LIGHT AND SHINY surfaces reflect a lot of IR falling on them!
Hot water pannels are a black surface however underneath is a shiny surface to keep absorbed heat in!
The pipes underneath the black matt surface is heated by this radiation from the sun!