A 1 kW-class multi-stage heat-driven thermoacoustic cryocooler system operating at liquefied natural gas temperature range

Abstract

This article introduces a multi-stage heat-driven thermoacoustic cryocooler capable of reaching cooling capacity about 1 kW at liquefied natural gas temperature range without any moving mechanical parts. The cooling system consists of an acoustically resonant double-acing traveling wave thermoacoustic heat engine and three identical pulse tube coolers. Unlike other traditional traveling wave thermoacoustic heat engines, the acoustically resonant double-acting thermoacoustic heat engine is a closed-loop configuration consists of three identical thermoacoustic conversion units. Each pulse tube cooler is bypass driven by one thermoacoustic heat engine unit. The device is acoustically completely symmetric and therefore “self-matching” for efficient traveling-wave thermoacoustic conversion. In the experiments, with 7 MPa helium gas as working gas, when the heating temperature reaches 918 K, total cooling capacity of 0.88 kW at 110 K is obtained with a resonant frequency of about 55 Hz. When the heating temperature is 903 K, a maximum total cooling capacity at 130 K of 1.20 kW is achieved, with a thermal-to-cold exergy efficiency of 8%. Compared to previously developed heat-driven thermoacoustic cryocoolers, this device has higher thermal efficiency and higher power density. It shows a good prospect of application in the field of natural gas liquefaction and recondensation.

Parameter sensitivity analysis of duplex Stirling coolers

“…One potential application is natural gas liquefaction, which is accomplished by burning part of the gas [1]. At present, the highest reported efficiency of heat-driven regenerative natural gas liquefaction has been achieved by burning about 30% to liquefy the rest [2,3].…”

A thermoacoustic combined cooling, heating, and power (CCHP) system for waste heat and LNG cold energy recovery

“…The key to achieving efficient energy conversion in a thermoacoustic system is to establish traveling-wave acoustic fields, i.e., the in-phase relationship between P1 and U1, across the regenerators [45]. Figure 9 shows the axial distribution of the phase difference between the pressure wave and volume flow rate in the thermoacoustic engine and heat pump.…”

A cascade-looped thermoacoustic driven cryocooler with different-diameter resonance tubes. Part Ⅱ: Experimental study and comparison

“…Developments in highefficient TADC natural gas liquefiers were accelerated by the development of the looped traveling-wave thermoacoustic engine (third generation). In 2015, a looped traveling-wave TADC operating at natural gas liquefaction temperatures was developed [26,27]. Experimental results showed that this system achieved a record exergy efficiency of 8 % and an overall cooling power of 1.2 kW at 130 K, which was capable of liquefying 65% of the natural gas while burning 35% natural gas.…”