Computer simulation results of three piston expander for Compressed Air Energy storage

The computer simulations as sensitivity analysis was conducted to examine the effects of piston speed, piston diameter, cut-off ratio, and supply pressure on the mechanical power at the expander shaft and the power conversion efficiency during air expansion. For this purpose, simulations were carried out for various points (different load torque) of the expander operation for specific construction (piston diameter) and process parameters (supply pressure, cut off ratio). Then, the simulation for specific operating points was averaged over the period of fixed expander operation in order to plot the operating characteristics of power, efficiency, torque and volumetric flow versus rotational speed.