研究工作温度为150℃/20~50℃/0℃的LaNi4.61Mn0.26Al013/La0.6Y0.4Ni4.8Mn0.2合金工质对,作出Van't-Hoff图,并推导了合金反应焓、反应熵、理论循环性能系数(ε0)和最低制冷温度.在此基础上设计反应床,搭建了高温导热油驱动的功能验证型金属氢化物间歇循环冷水系统;通过改变高温床平均温度,测定了循环性能和最低制冷温度的变化规律.试验结果表明合金对具有较好的吸氢动力性能和滞后小,低温合金吸氢反应焓达-27.1kJ/mol H2.反应床传质性能良好,但热导率仅为1.5 W/(m·K),导致循环时间过长且单位合金制冷量偏低.系统实现了间歇制冷循环,在150℃/30℃/0℃工况下获得了238 W的制冷功率,ε0达0.26.在试验温度范围内,随着高温床平均温度的升高,循环制冷量和ε0升高、最低制冷温度降低,这与金属氢化物制冷系统的理论相符.
A function proving automobile metal hydride (MH) refrigeration/air conditioning system is designed. The MH working pair LaNi4.61Mn0.26Al0.13La0.6Y0.4Ni4.8Mn0.2 with working temperature 150 ℃/20~50 ℃/0 ℃ is researched, their Van't-Hoff diagram is drawn and reaction enthalpy, entropy, theoretical cycling coefficient of performance (ε0) as well as minimum refrigeration temperature (θm) are deduced. Based on this working pair, reaction beds are designed, a function proving MH intermittent refrigeration water cooling system driven by heat conducting oil is constructed. The regulations of cycling performance and θm are determined by altering the average temperature of high temperature reaction beds. The test results show that the MH working pair has satisfied reaction dynamics and small hysteresis; The low temperature MH reaction enthalpy reaches -27.1 kJ/mol H2. The reaction beds have perfect mass transfer ability, while their heat conduction coefficients are merely 1.5 W/(m·K) which results in long cycle period and low cooling power per MH. Intermittent refrigeration cycle is achieved, 238 W cooling power is obtained at 150 ℃/30 ℃/0 ℃ with ε0 being 0.26. In the test range, with the growth of average temperature of the high temperature reaction beds, cooling power and system ε0 increase while θm decreases, which agrees well with MH refrigeration theories.