(338c) Cryogenic Hydrogen Adsorption On MOF-5 With Novel Microchannel Thermal Management System – Experiment and Simulation

Achieving a high volumetric storage density of hydrogen gas is a major challenge in the progress towards hydrogen-fueled automobiles.  Of the various storage methods, physical adsorbents show great potential, however, a reliable thermal management system is vital to provide quick, safe, and efficient charging and a controlled release of hydrogen gas on demand.

Experimental investigations have focused on the adsorption of hydrogen gas in a compressed adsorbent bed under cryogenic conditions.   The temperature distribution within the storage media is monitored and the storage capacity is determine to evaluate the affect of the addition of microscale-based heat exchanger device within the adsorption environment.  A mathematical model is used to numerically simulate the experimental process and evaluate system performance under various initial and operating conditions.

A novel microscale-based heat exchanger design takes advantage of 0.250 mm high features, which facilitate the flow of cooling fluid. The heat exchanger is fabricated by diffusion bonding of patterned stainless steel shims, resulting in an overall 0.250 mm thick resistance to thermal transport.  The microchannel structure uniformly distributes hydrogen gas into the adsorbent bed ensuring uniform adsorption and heat release.

 Liquid nitrogen flow through the microchannel device improves the storage capacity of a MOF-5 adsorbent system by 5% compared to non-cooled experiments, while providing a significant gain in storage capacity in comparison to a cryo-compressed storage system.

An expanded system investigation containing multiple adsorbent beds in contact with a 'numbered-up' microchannel heat exchanger system is tested under cryogenic conditions to ensure uniform flow and temperature distribution through each plate during the adsorption process.