Study On The Refrigeration Cycle Of The Metal Hydride Heat Pump

Under some special condition, a lot of alloys can react with hydrogen to be metal hydrides. The thermal energy discharged or charged from these reactions by some of the alloys such as the less common metals when absorbing or desorbing hydrogen can be used in cooling or heating process. Nowadays, as the Freon refrigerator is banned, various substances are made. Because of the characters of environment protecting and making use of the waste heat, metal hydride heat pump becomes to the most promising one of them. In order to guide the research on the prototype, the theoretical study must be done.Based on the introduction of the reaction characteristics and the former studies and applications of the metal hydrides, this paper studied the operation principle and characteristics of the metal hydride heat pump and gave some improving advices. A lumped-parameters numerical model was built to study the dynamic process of the refrigeration cycle with MmNi4.5Al0.5/MmNi4.2Al0.1Fe0.7. A test platform of the same parameters with LaNi5/LaNi4.7Al0.3 was built to validate the model. Both the temperature and pressure values of the whole cycle were recorded. The test results had the same trends with the theoretical results. The operation parameters which can influence the performance of the system were studied respectively. Based on the study result, the numerical model was refined with the improved parameters.The result showed that the performance of the system could be improved greatly. The most important parameters of the refrigeration cycle were the length of the refrigeration process and the heat transfer character of the reactors. Because the length of the refrigeration process was just a control parameter, the improvement of the heat transfer character of the reactors was the key point to improve the performance of the system.