(a) Tubes are spaced so that gas flows evenly over each one. 



(b) Tubas are closely packed. 



Figure 8. Metal-hydride/container concepts. 



is pumped through the hydrides which absorb energy and give off more 

 hydrogen which flows with the original cooler hydrogen out of the hydride 

 containment and back to the heat exchanger finishing its closed cycle. 

 Hydrogen can be tapped from this system downstream from the hydride 

 containment. 



The heat needed for these processes can be supplied from the exhaust 

 gases, the cooling water (provided the dissociation temperature is low 

 enough), from burning hydrogen, concentrated solar radiation, or from a 

 combination of these methods. As shown in Appendix B (Heating Analysis 

 section) there is an insufficient amount of high quality heat in the 

 exhaust gases of a typical internal combustion engine to release the 

 amount of hydrogen needed in the engine when magnesium nickel hydride is 

 used. This has proven to be the major problem with the magnesium-nickel 

 hydride. Sufficient heat is available to supply the dissociation energy 

 for the iron-titatium hydride, however; and a combination system of some 

 magnesium-nickel hydride and some iron- titanium hydride looks very 

 promising. An optimization analysis to find the miniraivm possible weight 

 for a dual system is planned but has yet not been executed. Alterna- 

 tively., the system might be cheaper and lighter by burning part of the 



36 



