Nowadays, natural gas is one of the most important energy resources around the world. The natural gas is always liquefied for distant transportation. Thus, the natural gas liquefaction technologies are of great importance. In this paper, a heat-driven thermoacoustic refrigerator is introduced for natural gas liquefaction application, which consists of a thermoacoustic Stirling heat engine, a thermoacoustic refrigerator and a linear alternator. The engine can convert heat from burning a small amount of natural gas to acoustic work, which drives the refrigerator to produce cooling power at desired temperature. The linear alternator provides a suitable working impedance of the refrigerator and convert the expansion acoustic work of the refrigerator to electricity. This electrical power can be used to power the pump, fan and other equipment to perform the liquefaction process. According to the simulation, a maximum cooling capacity of 340 W @ 110 K for one unit was obtained with 213 W electrical power. And the maximum exergy efficiency combined cooling and power of 21% could be achieved comparing that of 12.7% without electricity.
Keywords natural gas, liquefaction technology, thermoacoustic Stirling heat engine, thermoacoustic refrigerator, linear alternator