Development of a 5 kW traveling-wave thermoacoustic electric generator

Abstract

Traveling-wave thermoacoustic heat engine is a new type of external combustion heat engine, which is capable of converting thermal energy to acoustic power with advantage of heat source flexibility, reliability and efficiency. The generated acoustic power will be further converted into electricity by connecting linear alternator with the engine. This power generation system is called traveling-wave thermoacoustic electric generator. In this paper, a new traveling-wave thermoacoustic electric generator is proposed, which consists of a multi-stage traveling-wave thermoacoustic heat engine and linear alternators. The engine has several units connected end-to-end by slim resonance tubes to obtain a traveling-wave acoustic field in the regenerator, which is required by an efficient thermoacoustic heat engine. The alternator is connected as a bypass at the end of each resonance tube. Here, a three-stage traveling-wave thermoacoustic electric generator was developed. In the experiments, the maximum electric power of 4.69kW with thermal-to-electric efficiency of 15.6% and the maximum thermal-to-electric efficiency of 18.4% with electric power of 3.46kW were achieved with 6MPa pressurized helium, 650°C and 25°C heating and cooling temperatures. Additionally, the influence of the electric capacitance on the system performance was investigated, which may provide some clue to couple the alternator with the engine. So far, this performance is the best one of such type of machines. It is believed that this technology will be suitable for many applications in the energy area, such as solar energy, industrial waste heat and so on.