抄録
When a narrow duct (regenerator) is installed in a tube while the temperature ratio is higher than some critical value at both ends of the regenerator, the gas inside starts self-excited oscillation. Same phenomenon is used in thermoacoustic engines. To the contrary, it is possible to produce temperature gradient in the regenerator and achieve refrigeration by forcing the gas in the regenerator to oscillate. By combining a prime mover that generates sound wave out of heat and a refrigerator that uses sound wave, a refrigerator with no moving parts that is driven by heat input can be realized・However there is an issue to be solved before its practical use. While most industrial heat ranges from 100℃ to 300℃,critical onset temperature of a thermoacoustic engine is higher, ranging from 300℃ to 700℃. In order to solve this problem, a multistage thermoacoustic engine that can lower the critical onset temperature was suggested recently. It has been reported that critical onset temperature was successfully lowered with multistage amplification. However, a multistage thermoacoustic engine that uses multiple regenerators needs installation of regenerators not only at the peak of acoustic impedance distribution in real part, and therefore is generally inefficient・ In this paper, we calculated the configuration of the double-loop thermoacoustic refrigerator driven by a multistage thermoacoustic engine, and then experimented the cold heat exchanger temperature of the refrigerator and its efficiency when the hot heat exchanger temperature of the prime mover is changed. The double-loop thermoacoustic refrigerator driven by a multistage thermoacoustic engine realized -106.3℃ and the thermal efficiency showed 18%. The result shows that low temperature drive and high efficiency can both be achieved with a multistage thermoacoustic engine.
