Experimental study on the cooling performances of thermoacoustic heat exchangers

• Thermoacoustic engines (TAEs) employing various cooling methods are tested. • Comparisons are made between a heat pipe heat exchanger and a water-cooled heat exchanger. • TAEs with heat pipe heat exchangers can maintain self-excited acoustic oscillations. • We can use heat pipe heat exchangers to build “electricity-free" thermoacoustic devices. The design of heat exchangers is crucial for establishing a significant temperature gradient across a thermoacoustic stack, essential for efficient thermal-acoustic energy conversion. This study investigates various cooling methodologies in a standing-wave thermoacoustic engine (TAE), including heat pipe heat exchangers and water cooling. Results indicate that the TAE operating without cooling measures failed to sustain acoustic oscillations over time. In contrast, the TAE equipped with heat pipe heat exchangers was able to maintain long-lasting self-excited acoustic oscillations. Although the pressure amplitude and temperature difference were not the highest, the TAE with heat pipe heat exchangers demonstrated reliable operation without additional electricity consumption. The oscillation frequency and onset temperature differences showed minimal variation across different cooling methods, aligning closely with theoretical predictions. This study underscores the viability of heat pipe heat exchangers as effective passive cooling technology, laying the groundwork for future development of "electricity-free" thermoacoustic devices for sustainable heating, cooling, and power generation.