Two-stage travelling-wave thermoacoustic electricity generator for rural areas of developing countries

Thermoacoustic heat engines convert thermal power into acoustic power with no-moving parts, while the latter can be converted to electricity using linear alternators. Such thermoacoustic electricity generators can be a means of providing inexpensive electricity to developing countries using the simplest fabrication approaches. This paper shows a detailed study of a prototype waste-heat-driven, two-stage, looped-tube, travelling-wave thermoacoustic electricity generator with a branched linear alternator and tuning stub for acoustic impedance matching purposes. The generator was modelled and designed using DeltaEC. To keep the costs down, the working medium was atmospheric air, many resonator components were made of PVC pipes and fittings, heat exchangers were using automotive parts, while the linear alternator was a commercially available loudspeaker. The prototype generated 14.2 W of electrical power to a load of 9 Ω. The effects of matching stub length, variable resistive loads and heat inputs were investigated. The simulations and measurement results are presented and discussed in detail.