A copper tube heat exchanger is a device for transferring heat between two fluids. They are widely used in the petroleum industry, chemical processing, and power plants. A good example is the air-cooled heat exchangers used to cool engine oil in cars. Copper tube heat exchangers can be designed to transfer either sensible or latent heat (heat that accompanies a change in temperature), depending on the application. The heat exchange process uses fluid circulation within the tubes of the exchanger core to transfer thermal energy from one fluid to another.