High-efficiency natural gas fired 1 kWe thermoacoustic engine

Thermoacoustic engines have promised to be ultra-reliable heat engines. However, there have not been any reported examples of machines capable of displacing alternative technology in real-world applications to date. We have integrated a high efficiency (94%) recuperated burner, a high efficiency (87%) alternator and our highfrequency thermoacoustic engine to produce a compact 1 kW output 22% fuel-to-electric efficiency genset ready for real-world deployment. This fuel-to-electric efficiency is better than the previous best reported heat-toelectric efficiencies in a thermoacoustic engine. The many design innovations employed in the three subsystems of the genset to achieve this result are described. The electric output of 1 kW is large enough for numerous applications. This genset does not require any tight tolerance or exotic parts and should be amenable to low-cost volume manufacturing. The lack of any sliding or rotating parts results in a minimal maintenance extreme reliability engine. Experimental results are presented on the performance of the genset as a function of heater temperature, coolant temperature and output power. The predictions of the thermoacoustic model used to design the engine are compared with these experimental results.