Efficiency improvement of liquid piston compressor using metal wire mesh for near-isothermal compressed air energy storage application

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 nearisothermal compression. The compression efficiency of the liquid piston can be improved with the use of heat transfer enhancement mechanism inside the compression chamber. In this study, a novel heat transfer enhancement technique using metal wire mesh is experimentally tested in a liquid piston compressor to improve compression efficiency. Metal wire meshes of aluminum and copper materials and different wire diameters along with various stroke times of compression are considered in the experimental design. A distinctive Archimedean spiral form of metal wire mesh is considered to facilitate heat transfer in the axial and radial direction inside the compression chamber. Experiments are conducted for the compression of air from the atmospheric pressure to about 280 kPa pressure at various stroke times of compression. Results show that the peak air temperature was reduced by 26-33 K 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 the near-isothermal conditions. Furthermore, the isothermal efficiency of compression is evaluated to assess the potential for efficiency improvement with this technique. The metal wire mesh was observed to improve the isothermal efficiency of compression to 88-90% from the base efficiency of 82-84%. A 6-8% improvement in efficiency was observed at faster compression strokes signifying the efficacy of metal wire mesh to accomplish an efficient compression with a high power density.