OPTIMIZATION OF THERMOCONTROLLED TANK FOR HYDROGEN STORAGE IN VEHICLES

There is growing concern about the environmental pollution caused by v ehicular engines and the tendency to replace the dominant liquid hydro carbon fuels with cleaner alternative energy sources. Hydrogen is a pr omising alternative to liquid hydrocarbon fuels. It has many advantage s when injected directly into the cylinder of an internal combustion e ngine. However, when using compressed hydrogen gas for automotive appl ications, large and heavy tanks are required and when used in liquid f orm, expensive insulating materials and cryogenic pumps are required t o create the high pressure. A prototype composite vessel has been deve loped to supply hydrogen gas at high pressure required for direct inje ction without compressing gas or using any cryogenic pumps. This vesse l, called the thermocontrolled tank has been simulated and then tested to determine the rate of pressure and temperature rise in the tank. T he test results indicated that the liquid hydrogen can be brought from atmospheric pressure to the high pressure in a reasonable time period . The composite vessel design has been optimized for use in vehicles. The design problem was formulated as a multi-objective optimization ca se because of the presence of different conflicting objectives. Weight ing factors have been attached to the various objectives and then solv ed. Conclusions have been drawn from the tests, simulation and optimiz ation results which would allow the most effective storage of hydrogen in thermocontrolled tanks on vehicles equipped with direct gas inject ion. (C) 1997 International Association for Hydrogen Energy. All right s reserved.