Scott Backhaus is making waves- powerful acoustic waves that could cut the cost of industrial refrigeration. His tool is a thermoacoustic engine- a helium-filled pipe up to two meters long and 1.5 meters in diameter- that converts heat into sound waves, powering a chiller or producing electricity. When Backhaus began as a postdoc at Los Alamos National Laboratory five years ago, themoacoustic engines were mere lad curiosities whose inefficiency limited their usefulness. Within five months, Backhaus, who is now a technical staff member at Los Alamos, engineered a feedback loop in the pipes that produced 50 percent more power from the same amount of heat. The resulting waves were so strong they wrecked his prototype, but the efficiency boost had suddenly made the technology practical. This spring, industrial-gases firm Praxair tested a thermoacoustic chiller using Backhaus’s approach and intends to sell it for use in converting natural gas into a more easily transportable liquid form. The National Institute of Standards and Technology is also funding the development of Backhaus’s acoustic engines for use in natural-gas power plants.