Preliminary measurement campagne for experimental studies of the expansion cycle in a double-acting piston expander using intermittent supply of humid air in micro-CAES applications

The objective of the campaign was to analyze air expansion cycles in a double-acting piston expander within a micro-CAES installation, with an implemented control strategy based on pulse width modulation (PWM). The experimental investigations were conducted on a test rig developed by the EECS research group. The PWM function enables effective regulation of compressed air consumption by controlling the air intake into the chamber. Depending on the piston position during expander operation, the air mass flow rate is regulated using the PWM function. When the piston reaches the position x_PWM, a control signal is sent to the appropriate solenoid coil to close the valve. The system was equipped with sensors to monitor pressure, temperature, and piston position. Three experimental scenarios and one computational scenario were investigated. The first three scenarios concern experimental investigations of a single-cylinder piston expander operating in an idle regime (Scenario 1) and under mechanical load (Scenarios 2 and 3). Scenario 4 presents the results of numerical simulations for a three-piston expander. The three cylinders, connected via a crank mechanism, drive a shared shaft.