A proposed liquid hydrogen plant using a multi component refrigerant (MR) refrigeration system is explained in this paper A cycle that is capable of producing 100 tons of liquid hydrogen per day is simulated The MR system can be used to cool feed normal hydrogen gas from 25 degrees C to the equilibrium temperature of -193 C with a high efficiency In addition for the transition from the equilibrium temperature of the hydrogen gas from -193 degrees C to -253 C the new proposed four H(2) Joule-Brayton cascade refrigeration system is recommended The overall power consumption of the proposed plant is 5 35 kWh/kg(LH2) with an ideal minimum of 2 89 kWh/kg(LH2) The current plant in Ingolstadt is used as a reference, which has an energy consumption of 13 58 kWh/kg(LH2) and an efficiency of 21 28% the efficiency of the proposed system is 54 02% or more, where this depends on the assumed efficiency values for the compressors and expanders Moreover the proposed system has some smaller size heat exchangers much smaller compressor motors and smaller crankcase compressors Thus it could represent a plant with the lowest construction cost with respect to the amount of liquid hydrogen produced in comparison to today s plants e g in Ingolstadt and Leuna Therefore, the proposed system has many improvements that serve as an example for future hydrogen liquefaction plants (C) 2010 Professor T Nejat Veziroglu Published by Elsevier Ltd All rights reserved