Efficiency Improvement of a Liquid Piston Compressor Using Metal Wire Mesh

Intermittent nature of power from renewable energy resources demands a large scale energy storage system for their optimal utilization. Compressed air energy storage systems have the potential to serve as long-term large-scale energy storage systems. Efficient compressors are needed to realize a high storage efficiency with compressed air energy storage systems. Liquid piston compressor is highly effective in achieving efficient near-isothermal compression. Compression efficiency of the liquid piston can be improved with the use of heat transfer enhancement mechanisms inside the compression chamber. A high rate of heat transfer can be achieved with the use of metal wire mesh in the liquid piston compressor. In this study, metal wire meshes of aluminum and copper materials in the form of Archimedean spiral are experimentally tested in a liquid (water) piston compressor. Experiments are conducted for the compression of air from atmospheric pressure to 280–300 kPa pressure at various stroke times of compression. The peak air temperature is reduced by 26–33K with the use of metal wire mesh inside the liquid piston compressor. Both the materials are observed to be equally effective for temperature abatement. The use of metal wire mesh in liquid piston shifts the compression process towards near-isothermal conditions. Furthermore, the isothermal efficiency of compression is evaluated to assess the potential of efficiency improvement with this technique. The metal wire mesh was observed to improve isothermal compression efficiency to 88–90% from the base efficiency of 82–84%. A 6–7% improvement in efficiency was observed at faster compression strokes signifying effectiveness of metal wire mesh to accomplish efficient compression with high power density. Further investigations to evaluate the optimal configuration of the metal wire mesh will be useful to achieve additional improvement in efficiency.