heat exchanger is one that removes heat from a hot fluid to be stored for release later. These have recently found use in solar thermal energy systems where excess heat absorbed during the day is stored as molten salts for later release and use after the sun goes down. The heat is used ...
The change over temperature is called the “critical temperature.” Adding heat to the paper causes the paper to loose its color, an “endothermic” reaction. The reverse, going from colorless to colored, is an “exothermic” reaction and returns the heat....