Radiator

[citation needed] The Roman hypocaust is an early example of a type of radiator for building space heating.

A radiator may even transfer heat by phase change, for example, drying a pair of socks.

In practice, the term "radiator" refers to any of a number of devices in which a liquid circulates through exposed pipes (often with fins or other means of increasing surface area).

The term "convector" refers to a class of devices in which the source of heat is not directly exposed.

If air flow is obstructed by dirt or damage to the fins, that portion of the radiator is ineffective at heat transfer.

Radiators are used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plants and other places where heat engines are used (watercrafts, having an unlimited supply of a relatively cool water outside, usually use the liquid-liquid heat exchangers instead).

Starting in the 1970s, use of aluminium increased, eventually taking over the vast majority of vehicular radiator applications.

[citation needed] As electronic devices become smaller, the problem of dispersing waste heat becomes more difficult.

On the International Space Station, these can be seen clearly as large white panels attached to the main truss.