A lot of pure research got done a looong time ago, leading to discoveries and inventions, including thermocouples (Alessandro Volta in 1794, Thomas Johann Seebeck in 1821), solid state refrigeration (Jean Charles Athanase Peltier in 1834), photovoltaics (Edmond Becquerel in 1839), piezoelectricity (Carl Linnaeus and Franz Aepinus, mid-18th century), the Otto cycle (Nicolaus Otto, 1861, named for him but based on earlier work), and superconductivity (Heike Kamerlingh Onnes in 1911).
Cool you mention it... I have been experimenting with the Seebeck/Piezo effects recently. Aluminum and Iron is the most efficient combination. I am building an underground walk in refrigerator cooled with solar on large metal plates also taking advantage of the power output. No moving parts. :)
My mistake, too early and not enough coffee... Seebeck/Peltier. :)