Traveling‐Wave Thermoacoustic Heat Engines Attain High Efficiency

With continued concerns about greenhouse gases and ozonedepleting refrigerants, the quest for efficient and environmentally benign engines, heat pumps, and refrigerators remains important. For 20 years, one field of exploration has been thermoacoustics, which involves the interplay between thermodynamics and sound waves. Thermoacoustic engine research has focused almost exclusively on standing‐wave engines. Now Scott Backhaus and Greg Swift of Los Alamos National Laboratory have reported a new implementation of a traveling‐wave thermoacoustic engine—a pistonless Stirling engine that's almost twice as efficient as standing‐wave thermoacoustic engines.