heat sink vs space heater

heat sink

noun
  • A material capable of absorbing heat. 

  • An object, system or environment that absorbs and dissipates heat from objects in thermal contact (either direct or radiant) with it. 

  • A place toward which the heat moves in a system. 

space heater

noun
  • A portable heating appliance used to warm an area or room. 

How often have the words heat sink and space heater occurred in a corpus of books? (source: Google Ngram Viewer )