Solar furnace melts through steel in seconds

By SkySolar

Say hello to this ginormous solar furnace. This 1949 giant Mont-Louis solar furnace can barbecue wood and melt steel in seconds.

1949 Solar Furnace

This double-mirror solar furnace was constructed in 1949 by engineer Félix Trombe in the citadel of Mont-Louis. It concentrates the sun’s rays to melt anything that is within its 3,000 C beam range. It was designed for high-temperature experiments on materials and to show how to fire ceramics without using wood.


The solar furnace was relocated from the citadel to a location near the city walls in 1975 to be used for educational purposes and it remains there today. It can concentrate 50 kilowatts of solar energy just in an area of few square centimeters on a sunny day. It’s enough to ignite wood and melt steel in a matter of seconds.

In 1970, the largest solar furnace was constructed in Odeillo due to the success of Mont-Louis. The Odeillo has a 1830 square-meter parabolic reflector illuminated by 63 heliostats. It is used by France’s National Center for Scientific Research for experiments including thermal shielding for spacecraft, developing cladding for the inside of nuclear reactors and developing ways of producing synthetic fuels without carbon emissions.

Today, the same technology of harvesting solar energy with mirrors is becoming popular. Large solar farms with thousands of mirrors concentrating the sun’s rays onto a central core to harness the enormous amount of heat energy generated are extremely effective ways of producing zero emission energy, albeit at a risk to birds flying by!

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