Thermoacoustically driven single-stage pulse tube refrigerator below 50 K

Thermoacoustically driven pulse tube refrigerator represents an emerging, eco-friendly approach to achieve low temperatures. This technology offers several advantages, including the ability to utilize low-grade energy, high reliability, and long lifespan. However, the current thermoacoustically driven single-stage pulse tube refrigerator (TDSPTR) above 100 Hz has limitations in reaching lower minimum cooling temperatures. This paper introduces a looped TDSPTR system, incorporating four thermoacoustic engines that enable cascaded utilization of waste heat, along with a single-stage pulse tube refrigerator featuring a high regenerator temperature gradient of 6.857 K/mm. Results indicate that the thermoacoustically driven single-stage pulse tube refrigerator enables cascading utilization of waste heat from multiples sources at 654 K, 783 K, and 424 K, achieving a record-low temperature of 48 K in TDSPTR system operating at 100 Hz. An acoustic pressure amplifier is used to connect the loop and the refrigerator, enhancing the pressure amplitude by a factor of 2.49. Furthermore, the 100 Hz TDSPTR system demonstrated a cooling power of 3 W at 74.0 K, highlighting the potential for cascading utilization of low-grade energy to achieve low-temperature cooling.