| Description |
In this thesis, the design and analysis of a dual bed metal hydride thermal battery is presented. First, a computer code that sizes the hydride bed cell to meet prescribed heat transfer goals is presented. A hypothetical bed shape is chosen and a matched pair of hydrides is optimized using the model. Various considerations are taken into account in selecting an appropriate con guration including ice buildup on the low temperature bed, pressure drop along the heat exchanger and cost. Second, a dynamic lumped capacitance kinetic model detailing the rate of hydrogen absorption and temperature change is presented. The model is validated against published data for a one bed constant pressure con guration, experimental data gathered for a second one bed constant pressure con guration and nally for a two bed thermal battery operating in heat pump mode. Third, it was found that each hydride should experience maximum kinetic rates at a temperature explicitly de ned by the hydrides fundamental properties and the local hydrogen pressure. Finally, a nite di erence model is developed to predict the radial temperature variation across the hydride cell cross section. It was found that the lumped capacitance model provides reasonable predictions of average cross-section temperatures as long as the kinetic rates, dimensions and thermal conductivity are such that a derived critical dimensionless ratio is less than 0.1. |
