Analysis of multi-cylinder type liquid piston Stirling cooler

The development of cooling technology driven by low-grade heat sources and having a straightforward structure is crucial for various cooling needs in rural areas. For this purpose, a multi-cylinder type liquid piston Stirling cooler was investigated. It consisted of unit sections connected in a ring shape. Each unit section, which can function either as an engine or cooler unit, was made from a water column in a U-shaped tube and an air-filled tube installed with a regenerator and a pair of heat exchangers. The cooling performance and its relationship with acoustic fields were evaluated numerically and experimentally. When using a single cooler unit configuration, the lowest cooling temperature reached �2°C with a heating temperature of 218 °C. The cooling power of 23.5 W and coefficient of performance of 0.19 were achieved at a cooling temperature of 20 °C with the same heating temperature in the case of the two cooler unit configuration. These results were obtained by adjusting the liquid column level in the U tube at certain unit sections. The correlation between the improvement in cooling performance and the associated acoustic field modification was investigated based on the breakdown and recovery of the symmetry of the acoustic fields. In addition, a cooler box was made to demonstrate the possible application of the heat-driven cooler. The result showed that the temperature inside the cooler box achieved 3.6�6.6 °C. This study presents a new cooling technology suitable for multiple cooling purposes in rural areas.