thermopile

/ˈθɜrməˌpaɪl/
noun
  1. A device that converts heat energy into electrical energy, made of a series of thermocouples connected together.
    • A thermopile is used in some gas stoves to generate electricity for the igniter.
    • The spacecraft's power system relies on a thermopile to turn heat from radioactive decay into electricity.
    • Engineers designed a small thermopile to harvest waste heat from industrial machines.