Experimental studies on a metal hydride–based single bed sorption cryocooler

Abstract

The present work deals with the development of a MmNi 4.5 Al 0.5 -based single bed sorption precooled Linde-Hampson cryocooler. The working substance and the precooling refrigerant used in this investigation were hydrogen and liquid nitrogen, respectively. The gaseous hydrogen could be compressed merely in the metal hydride reactor in comparative ease and thus an MmNi 4.5 Al 0.5 -based metal hydride reactor was used to develop a single bed sorption compressor. The hydrogen is allowed to compress at two different supply pressures of 5 and 10 bar at a constant absorption temperature of 20°C. Desorption temperatures were varied at 65°C, 75°C, and 80°C. Maximum discharge pressures were obtained at a desorption temperature of 80°C as 21 and 27 bar, respectively. The entire cryocooler was designed, fabricated, and tested on the sorption cryocooler. Furthermore, compressed high-pressure gaseous hydrogen was allowed to flow in the cryocooler at a flow rate of 40 standard cubic centimeter per minute. The minimum temperatures obtained in the evaporator at discharge pressures of 21 and 27 bar were 111 K and 107 K, respectively. K E Y W O R D S cool-down characteristics, heat exchanger, hydrogen, metal hydride reactor, sorption cryocooler