Characterization and Performance Testing of Two-Stage Reciprocating Compressors during the Dynamic Charging of a Tank with Air

Relatively little information is available in the literature with respect to performance of compressors used during the dynamic charging process of a tank. Therefore, work presented in this paper focuses on experimental performance testing of a two-stage reciprocating compressor system using air as the working fluid during the dynamic charging of a tank. A new open loop system test stand, has been designed and built to conduct the dynamic compressor performance tests. Testing was conducted from an initial pressure of 101.3 kPa to a final tank pressure of 3600 kPa. To achieve the final pressure of 3600 kPa, two hermetic reciprocating compressors were used in series. Due to the nature of the charging process, initially only the first stage compressor was activated until the tank pressure reached a level that required activation of the second stage compressor. Along with the experimental effort, a simulation model to predict compressor dynamic performance has been developed. In this model, the initial clearance factors of the two compressors were calculated based on available compressor maps. The calculated clearance factors were then used as inputs to the dynamic model. The entire charging process was then simulated to provide the compressor performance data as a function of time. Finally, the predicted performance was validated using the acquired test data also presented in this paper.