Charging Dynamics of Multi-Stage Reciprocating Compressor for Micro-Scale Compressed Air Energy Storage System

This study presents a comprehensive experimental and numerical analysis of charging dynamics in micro-scale compressed air energy storage systems employing multi-stage reciprocating compressors. The experimental apparatus features a 5–40 MPa four-stage reciprocating compressor coupled with a 0.45 m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> pressure vessel, with charging characteristics monitored over 40-minute operational cycles. Key findings demonstrate near-linear pressure growth in the storage vessel under design-near conditions (>15 MPa), with experimental results showing <5% deviation from numerical predictions. Sub-optimal operation (<15 MPa) reveals significant discrepancies due to breakdown of the equal pressure ratio assumption across compression stages. Power consumption analysis indicates 94.9% prediction accuracy under design conditions, decreasing to 84.2% at off-design operation. Critical system integration requirements are established, including the necessity for compressor capacity. These findings provide essential guidelines for optimal component matching in renewable energy-integrated CAES systems.