Thermoelectricity (D+70)

  D+70+0 Thermocouple and thermopile, both make electricity from heat.
  D+70+2 Thermocouple magnet: Flame with water cooling holds weight.
  D+70+4 Thermocouple magnet: Flame with ice bath, holds weight.
  D+70+6 Thermoelectric fan: Fan runs off of hot and cold water.
  D+70+8 Peltier junction: Forward current freezes water drop, reverse boils.