Standardized hydrogen storage module with high utilization factor based on metal hydride-graphite composites

Abstract

In view of hydrogen based backup power systems or small-scale power2gas units, hydrogen storages based on metal hydrides offer a safe and reliable solution. By using Hydralloy C5 as suitable hydride forming alloy, the present tank design guarantees very simple operating conditions: pressures between 4 bar and 30 bar, temperatures between 15 °C and 40 °C and minimal efforts for thermal management in combination with fast and constant charging and discharging capabilities. The modular tank consists of 4 layers with 5 reactor tubes each that are filled with metal hydride-graphite composites of a diameter of 21 mm. Experiments show that each layer of this tank is able to desorb the desired amount of hydrogen for a fuel cell operation at electrical power of 160 Wel for 100 min reaching a utilization factor of 93% of the stored hydrogen at RC. Furthermore, the experimental results of modularity, increasing loads and the electric air ventilation are presented

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

“…The only commercially available Laves phasebased hydride-forming class of alloys, which is already successfully in application, is so-called Hydralloy [450,[478][479][480][481][482][483]. Hydralloy is always based on a C14 Laves phase containing Ti and Mn in a 1:1.5 ratio as main constituents.…”

“…Hydralloy is always based on a C14 Laves phase containing Ti and Mn in a 1:1.5 ratio as main constituents. [481,[483][484][485].…”

Metal Hydride‐Based Hydrogen Storage Tank Coupled with an Urban Concept Fuel Cell Vehicle: Off Board Tests

“…Metal hydride reactors containing an AB 2 ‐type material were studied as H 2 supply for FC in several sizes and with different heat transfer media: this allowed to determine the limiting issues and to implement techniques to moderate the related problems, such as compacting the material and adding graphite to increase the thermal conductivity . After developing this enhanced heat conductivity in AB 2 composites, a storage system based on modules was also designed; the ingenious addition of aluminum foam to enhance heat transport externally allowed positive results and a high utilization factor, exploiting only air ventilation at low power . Slightly bigger storages, conceived and tested in integrated systems with FCs, can also profitably include room temperature hydrides as storage materials; in this case the preferred family is AB 5 : more than 3 m 3 for stationary applications .…”

Metal hydride reactor for dual use: Hydrogen storage and cold production

“…To this end, any external cooling circuit that is usually implemented for air-conditioning systems is removed, and an air-cooled modular hydride reactor with a simple tubular geometry is considered. A similar geometry has been studied previously as experimental work for stationary hydrogen storage [19], however, without considering the cooling effect. In the present case, it is considered that the air-cooled hydride reactor will directly be connected with the passenger cabin.…”

“…In this system, the amount of thermal power required to cool air is directly related with the given hydrogen flow rate, as well as the enthalpy of the metal hydride chemical reaction. Thus, the focus of this study is on two aspects: Which hydrogen storage utilization factor, defined as the ratio between the "mass of hydrogen released with relevant flow rates" and the "maximum mass of stored hydrogen that can be discharged" at the corresponding operation conditions [19], can be reached for the reactorthus how "good" is the reactor as hydrogen storage module. Furthermore, at which temperature level can the cooling effect be providedthus is there a sensible (cooling) effect in the passenger cabin.…”