Leonardo da Vinci designed a solar furnace to concentrate sunlight for high-temperature experiments.
His notes describe using mirrors to gather and focus solar rays. Concentrating light into a small area raises the temperature there, making the principle useful for heating, melting, or industrial experiments. Leonardo was interested in solar energy as a practical source of heat, not merely as an astronomical curiosity.
A solar furnace is different from a solar panel. A panel converts sunlight into electricity, while a solar furnace concentrates radiant energy as heat. Leonardo’s proposal should also not be confused with a modern industrial solar tower, which uses many computer-controlled mirrors and a receiver. His Renaissance design was a conceptual arrangement of mirrors, and there is no clear evidence that he completed a large working furnace.