Hydrogen storage systems (HSSs), are the backbone of feasible hydrogen economy. To provide a reliable renewable energy system, safe, cost effective and compact HSS is due. Physical storage systems involve the compressed gas, liquid and cryo-compressed techniques while material based one involves adsorptive materials, metal hydrides and chemical storage materials. In this paper, the features of a variety of HSSs are impartially discussed. The technical comparative analysis of the different physical and material based types of HSSs illustrates the paradoxical inherent features, including gravimetric and volumetric storage densities and parameters associated with storage and release processes, among these systems. Accordingly, no ideal hydrogen storage technique can be considered the best-fit for all stationary and automotive applications. Therefore, not only a unique HSS solution can properly provide the needs, but a set of complementary HSS solutions which may offer the system designer several options. This set of options can be hardly interpretable in case of the unclear definition of the application needs which may be time variant. Inside this review, the critical insights and recommendations about suitable applications for storage systems are provided. Different standards and codes alongside the corresponding tests are demonstrated for the different storage technologies. Moreover, storage vessels research work is overviewed for the different hydrogen storage technologies. In addition, the failure behaviour, criteria and prediction models are investigated for composite vessels subjected to high pressures and extreme temperatures degrading their mechanical behaviour and failure resistance.

Hydrogen storage technologies for stationary and mobile applications: Review, analysis and perspectives

A review is presented for the research development of Stirling cycle engines for recovering low and moderate temperature heat. The Stirling cycle engines are categorized into four types, including kinetic, thermoacoustic, free-piston, and liquid piston types. The working characteristics, features, technological details, and performances of the related Stirling cycle engines are summarized. Upon comparing the available experimental results and the technology potentials, the research directions and the possible applications of different Stirling cycle engines are further discussed and identified. It is concluded that kinetic Stirling engines and thermoacoustic engines have the greatest application prospect in low and moderate temperature heat recoveries in terms of output power scale, conversion efficiency, and costs. In particular, kinetic Stirling engines should be oriented toward two directions for practical applications, including providing low-cost solutions for low temperatures, and moderate efficient solutions with moderate costs for medium temperatures. Thermoacoustic engines for low temperature applications are especially attractive due to their low costs, high efficiencies, superior reliabilities, and simplicities over the other mechanical Stirling engines. This work indicates that a cost effective Stirling cycle engine is practical for recovering small-scale distributed low-grade thermal energy from various sources.

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Stirling cycle engines for recovering low and moderate temperature heat: A review

http://eprints.gla.ac.uk/69764/1/69764.pdf

Travelling-wave thermoacoustic electricity generator using an ultra-compliant alternator for utilization of low-grade thermal energy

Zhanghua Wu

Papers

Development of a 5 kW traveling-wave thermoacoustic electric generator

Modeling and experimental investigation of a free-piston Stirling engine-based micro-combined heat and power system

A solar-powered traveling-wave thermoacoustic electricity generator

Development of a 3 kW double-acting thermoacoustic Stirling electric generator

Investigation on a 1kW traveling-wave thermoacoustic electrical generator