Masonry oven India, tandoors are traditional clay ovens, although these days modern electrically fired tandoors are available. The open-topped tandoor is a transitional design between the earth oven and the Roman-plan masonry oven. In the precolumbian Americas, similar ovens were often made of clay or adobe and are now referred to by the Spanish term "horno" (meaning "oven"). Horns are also traditional in the American Southwest. The traditional direct-fired masonry design is often called a "Roman" or "black" oven and dates in Western culture to at least the Roman Republic. It is known as a black oven because the fire generates soot
Ceramic heat cell Ceramic heat cell A ceramic heat cell, also known as Caloric Porous Structure Cell (CPSC), is a ceramic device to burn a fuel without flame, converting the thermal energy to mechanical work. In principle any fuel that can be vapourised and pre-mixed with air can be used. "Ultra vaporized steam" replaces the exploding air/fuel mixture as the work medium. The flameless combustion keeps emissions of hydrocarbons, carbon monoxide, and nitrous oxides extremely low. Exhaust gas can be recirculated, which further reduces emissions. A ceramic heat cell made by German firm Enginion is claimed to generate up to 30 megawatts of