Sun-powered, long-distance chemistry
Israeli researchers have successfully tested a device that converts solar energy into chemical energy, part of a proposed chemical system for transporting energy economically over long distances. Designed and built by the Sandia National Laboratories in Albuquerque, N.M., the device combines a solar collector with a chemical reactor.
The collector concentrates sunlight to vaporize sodium metal. The hot metal vapor is then conducted to the chemical reactor, where it condenses and releases heat to drive a chemical reaction between methane and carbon dioxide. The products are hydrogen and carbon monoxide, which can be transported as room-temperature gases. Piping these gases instead of a hot fluid reduces the possibility of significant heat losses and circumvents the need for heavy insulation. At their destination, the gases can be converted back into a hot fluid and used to heat buildings or generate electricity.
Last year, Sandia completed its initial laboratory tests on the concept, using electric heaters as sources of heat. The recent field tests, on a 10-times-larger scale and with concentrated sunlight, took place in a solar furnace at the Weizmann Institute of Science in Rehovot, Israel.