Thermal radiation is energy transfer by electromagnetical waves.
All objects emit thermal radiaton.
The hotter/more energy an object is the more energy it emits.
Dark matt surfaces are better emitters of thermal radiation than light shiny surfaces.
Dark matt surfaces are better absorbers of thermal radiation than light shiny surfaces.
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Conduction and Convection
Conduction in a metal is due to mainly to free electrons inside the metal.
Non-metals are generally poor conductors as they do not contain free electrons.
Materials such as fiberglass are good insulators because they contain pockets of trapped air.
Convection takes place only in fluids (liquids and gases)
Heating a fluid makes it less dense.
Convection is due to a hot liquid or gas rising.
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Heat transfer by design
Small objects lose heat more easilly than large objects.
Heat loss from a building can be reduced by using: aluminum foil behind radiators, cavity wall insulating, double/ triple glazing, loft insulation and under floor insulation.
Example: radiators have a large surface area to disperse its heat quickly.
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