In terms of adsorption compressors, corresponding structures can be seen as a thermodynamic engine by using heat exchange as the driving force of compression in which low-pressure hydrogen is injected into high-adsorption potential porous materials in a compressor, and physical hydrogen adsorption is desorbed at a certain volume after reaching high pressures under specific temperature and pressure conditions. And depending on the physical nature of porous materials, the flow of compressed hydrogen is obtained through multiple cycles of adsorption/desorption.

As for metal hydride compressors (MHCs), they are made up of a slender central artery to distribute hydrogen inside a reactor and an annular space between the artery and a tank wall for metal hydride placement. In principle, low-pressure hydrogen can enter the metal hydride tank through the central artery and diffuse into the metal hydride bed to allow for the exothermic reaction of hydrogen absorption in which hydrogen compression can occur due to the continuous cooling and heating of the metal hydride as controlled by heat transfer.

Electrochemical hydrogen compressors (EHCs) are devices that use the electrochemical principle to compress low-pressure hydrogen into high-pressure hydrogen in which the application of voltage can lead to the generation of localized pressure difference due to hydrogen oxidation at anodes and hydrogen reduction at cathodes. Here, protons and electrons produced through hydrogen oxidation are transported to the cathode side through a proton exchange membrane (PEM) (for protons) and an external path (for electrons) to recombine to form new hydrogen molecules  in which electric power is converted to chemical potential in high-pressure hydrogen gas through the electrochemical process.