Experimental research on refrigeration characteristics of a metal hydride heat pump in auto air-conditioning

Refrigerating experiments of metal hydride heat pump were conducted under three operating temperatures. The high pressure reaction bed is filled with LaNi 4.61 Mn 0.26 Al 0.13 , while the low pressure reactor is filled with La 0.6 Y 0.4 Ni 4.8 Mn 0.2 . The results show that there are four processes for high-pressure reaction bed, and three processes for low-pressure reaction bed. The lowest refrigerating temperatures at the three operating temperatures are 6.5, 2.5, and 1.9 ∘ C , respectively. Cooling power output cannot be kept constant and becomes smaller as the refrigerating process goes on. As T h increases, the refrigeration cycle time, temperature and pressure of high reaction beds all climb and COP and cooling power output keep increasing. There is a great deviation between the static van’t Hoff plots and the actual dynamic lnP–1000/T relations under the operating temperature of T h / T m / T l = 150 ∘ C / 30 – 32 ∘ C / 20 ∘ C .