Two-Stage Thermoacoustic Electricity Generator for Waste Heat Recovery

This paper presents the design, construction and tests of a two-stage traveling-wave thermoacoustic electricity generator. The engine designed has two stages with a Linear Alternator connected in between two points having equal but out of phase acoustic pressure amplitudes. The connection of Linear Alternator in this configuration allows it to be run by the effect of acoustic pressure on both sides and work in a "push-pull" mode. Pressurized helium at 28 bar is used as working gas and operating frequency is 54.68 Hz. In the experiments, a maximum generated electricity and thermal-to-electric efficiency of 48.6 W and 2.7% are obtained, respectively, when the temperature difference across the regenerator reaches 300˚C at 30.8 Ω load resistance. The research results shown in this paper demonstrate that two identical half-wave length stages can run a linear alternator in “push-pull” mode.