Experimental characterization and performance study of an ammonia-water-hydrogen refrigerator

We present in this paper an experimental study of a commercial diffusion-absorption refrigeration machine (DAR) operating on the Platen and Munters cycle. The temperatures at the inlet and outlet of every component of the machine, as well as the cabinet and ambient temperature are measured continuously. The tests are repeated for various electric power inputs to the refrigerator. The global heat transfer coefficient of the cabinet (UA)cab is determined using both theoretical and experimental methods. This coefficient is found equal to 0.2 W/°C. The global heat transfer coefficient of the evaporator (UA)evap is deduced using dynamic and steady state methods. This global heat transfer coefficient (UA)evap is found equal to 0.3 W/°C. Finally the cooling capacity of the unit and the coefficient of performance are evaluated. The heating power supply to the generator necessary to ensure the desired state of this machine is found to be in the range of 35 W-45 W.