Review of Hydro-Pneumatic Accumulator Models for the Study of the Energy Efficiency of Hydraulic Systems

Abstract

This review article deals with hydro-pneumatic accumulators (HPAs) charged with nitrogen. The focus is on HPA models used in the study of the energy efficiency of hydraulic systems. Hydraulic circuits with HPA are presented along with their various applications for delivering the required volume of fluid, maintaining the required pressure, ensuring safe operation, safety stop, leak compensation, fluid volume change compensation, pulsation damping, and pressure shock absorption. A general regenerative hydraulic system and a general hybrid hydraulic system are also presented. The review focuses primarily on HPA computational, dynamic, and simulation models. Basic HPA calculation parameters and computational models of energy storage and thermodynamic cycle are presented. Various computational and dynamic models of HPA have been defined, such as the thermodynamic model, simulation model, dynamic model, pulsation damper model, and shock pulse damper model. Research projects that have used HPA in industrial hydraulic systems are reviewed, such as those maintaining operating pressure in an industrial 80 MN open-die hydraulic forging press and acting as a shock pulse absorber in the lifting and levelling module of a tracked mobile robotic bricklaying system. The development of energy storage technology in HPA from various sources is now a global challenge.

A Review of Energy Overconsumption Reduction Methods in the Utilization Stage in Compressed Air Systems

“…Researchers have also explored dual-pressure systems, where different supply pressures are set for the extend and retract movements. Harris et al [17], Dindorf et al [25], Beater [28] claimed 20-50% energy savings using the dual-pressure approach: that is, applying different pressures for the extend and retract movements, respectively. The disadvantage of the solution is the need to use two pressure regulators separately for each movement.…”

“…Depending on the purpose of the air, there are seven classes that differ in the content of moisture, solid particles, and oil. In some applications, the air is also lubricated [25]. The compressed air prepared in this way goes to the tank.…”

“…Unger and Radgen [8], Merkelbach et al [18], and Herrera et al [19] estimate that the energy efficiency of pneumatic systems can be improved by up to 80%. Dindorf et al [20,21] presented an overview of compressed air receiver tanks and their impact on energy efficiency and storage. Trianni et al [22] focused on assessing energy efficiency measures in terms of economics, energy, complexity, compatibility, and observability factors.…”

“…Negligence in the air preparation system can lead to disruptions and failures in system operation, affecting filters and mufflers. The use of poor-quality compressed air can result in various issues, such as reduced clamping force, slower movement speed, pressure drop, faulty valve operation, and overall deterioration of system components [25]. • Diagnostic devices: Devices designed to evaluate pneumatic power parameters, such as the diagnostic tool created by Cai et al [63,64], can be beneficial for system diagnostics.…”