Experimental evaluation of heat pump performance in connection with metal hydride properties

Abstract

Abstract Hydriding and dehydriding reactions have been applied reversibly in a continuous manner to convert thermal energy into such invaluable types of energy as high pressure steam, electric power, drying and dehumidifying enthalpies, compressed gas enthalpy and so forth. The operational characteristics and efficiency of these systems are strictly dependent on the hydride properties (especially on the amount of hydrogen gas transferred through dehydriding and hydriding reactions between two metal hydrides that behave as hydrogen donor and hydrogen acceptor). In order to improve the performance in these cyclic applications of hydride reactions, the hydrogen gas transferable per unit mass of hydriding alloy per unit time must be increased; this can be achieved by improving the hydride properties and the heat transfer characteristics of the metal hydride bed. Heat pump performance is discussed here in connection with the hydride properties. A new ternary hydride system is introduced which has a high temperature gain and efficiency through cascade reactions between three metal hydrides.