This paper presents the results of numerical simulations examining the thermodynamic processes during hydraulic hydrogen compression, using COMSOL Multiphysics^® 6.0. These simulations focus on the application of hydrogen compression systems, particularly in hydrogen refueling stations. The computational models employ the CFD and heat transfer modules, along with deforming mesh technology, to simulate gas compression and heat transfer dynamics. The superposition method was applied to simplify the analysis of hydrogen and liquid piston interactions within a stainless-steel chamber, accounting for heat exchange between the hydrogen, the oil (working fluid), and the cylinder walls. The study investigates the effects of varying compression stroke durations and initial hydrogen pressures, providing detailed insights into temperature distributions and energy consumption under different conditions. The results reveal that the upper region of the chamber experiences significant heating, highlighting the need for efficient cooling systems. Additionally, the simulations show that longer compression strokes reduce the power requirement for the liquid pump, offering potential for optimizing system design and reducing equipment costs. This study offers crucial data for enhancing the efficiency of hydraulic hydrogen compression systems, paving the way for improved energy consumption and thermal management in high-pressure applications.

This paper presents the results of numerical simulations examining the thermodynamic processes during hydraulic hydrogen compression, using COMSOL Multiphysics® 6.0. These simulations focus on the application of hydrogen compression systems, particularly in hydrogen refueling stations. The computational models employ the CFD and Heat Transfer modules, along with deforming mesh technology, to simulate gas compression and heat transfer dynamics. The superposition method was applied to simplify the analysis of hydrogen and liquid piston interactions within a stainless-steel chamber, accounting for heat exchange between the hydrogen, the working fluid, and the cylinder walls. The study investigates the effects of varying compression stroke durations and initial hydrogen pressures, providing detailed insights into temperature distributions and energy consumption under different conditions. The results reveal that the upper region of the chamber experiences significant heating, highlighting the need for efficient cooling systems. Additionally, the simulations show that longer compression strokes reduce the power requirement for the liquid pump, offering potential for optimizing system design and reducing equipment costs. This study offers crucial data for enhancing the efficiency of hydraulic hydrogen compression systems, paving the way for improved energy consumption and thermal management in high-pressure applications.

Hydrogen compression is a critical process in hydrogen storage and distribution, particularly for energy infrastructure and transportation. As hydrogen technologies expand beyond limited industrial applications, they are increasingly supporting the green economy, including offshore energy systems, smart ports, and sustainable marine industries. Efficient compression technologies are essential for ensuring reliable hydrogen storage and distribution across these sectors. This study focuses on optimizing hydrogen compression using a Liquid Piston Hydrogen Compressor through numerical simulations and scaling analysis. The research examines the influence of compression chamber geometry, including variations in radius and height, on thermal behavior and energy efficiency. A computational model was developed using COMSOL Multiphysics^® 6.0, incorporating Computational Fluid Dynamics (CFD) and heat transfer modules to analyze thermodynamic processes. The results highlight temperature distribution in hydrogen, working fluid, and chamber walls at different initial pressures (3.0 MPa and 20.0 MPa) and compression stroke durations. Larger chamber volumes lead to higher temperature increases but reach thermal stabilization. Increasing the chamber volume allows for a significant increase in the performance of the hydraulic compression system with a moderate increase in the temperature of hydrogen. These findings provide insights into optimizing hydrogen compression for enhanced production and broader applications.

Hydrogen technologies are increasingly important for energy storage and decarbonization of industrial and transport sectors. Hydrogen compression is accompanied by thermal effects that influence energy efficiency and thermal loading of compression systems. This study numerically investigates the influence of compression chamber wall thickness on heat transfer and wall temperature evolution during hydrogen compression in a liquid piston compressor. An axisymmetric multiphysics model was used to simulate a single compression stroke at initial pressures of 3–20 MPa, stroke durations of 0.5–20 s, and chamber wall thicknesses of 2.5–10 mm. The simulations show that wall temperature rise increases with compression stroke duration and initial pressure, while increasing wall thickness reduces the per-stroke temperature increase due to higher thermal inertia. The results also indicate non-uniform wall heating, with the highest temperatures occurring in the upper region of the compression chamber.

The authors perform a comparative analysis of the efficiency of two types of low-power wind energy conversion systems with horizontal and vertical axis in the meteorological conditions of Latvia. The analysis is based on long-term wind speed measurements over the period of two years conducted by a network of 22 observation stations at the height of 10 m above the ground. The study shows that in the conditions of Latvia wind turbines with a horizontal axis are expected to work with greater efficiency than similar installations with a vertical axis. The paper presents the models of the spatial distribution of average wind speed, Weibull wind speed frequency distribution parameters and the values of the expected operational efficiency for small wind turbine generators. The modelling results are presented in the form of colour contour maps. Overall, the results of the study can serve as a tool for forecasting annual energy production and for estimating the feasibility of commercial use of wind energy at the height of 10 m in the territory of Latvia.

Hydrogen compression is a critical interface between production, storage and end use in decentralized green hydrogen infrastructure, where fluctuating electrolyzer output and intermittent demand require operation over variable pressure and flow conditions. This review provides a cross-technology and application-oriented assessment of conventional mechanical, liquid-piston, electrochemical, metal-hydride and hybrid compression systems using common criteria including pressure ratio, specific energy consumption, thermal behavior, hydrogen purity, dynamic flexibility, reliability, scalability and technology readiness. The comparison shows that mechanical compressors remain the reference choice when high pressure, high throughput and commercial maturity dominate. Liquid-piston systems may offer advantages where thermal management and near-isothermal operation are priorities, but their performance depends on working-fluid properties, interface stability, chamber scaling and hydraulic efficiency. Electrochemical compressors are attractive for compact, high-purity and moderate-flow applications, although membrane durability, hydrogen crossover and water management remain key barriers. Metal-hydride systems are most relevant where low-grade or waste heat is available, while hybrid systems can distribute complementary compression functions between stages. Overall, no single technology is optimal; selection should consider the complete operating envelope and integration with electrolyzer operation, buffer storage and downstream demand. Future development requires standardized reporting, long-term cyclic validation, and realistic lifetime and cost data.