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Abstract
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A novel structure for hydrogen liquefaction is developed and thermodynamically analyzed. The modified
structure, which produces approximately 290 tons of liquid hydrogen (LH2Þ per day, consists of a basic
hydrogen liquefier system, an organic Rankine cycle, an absorption refrigeration system, and solar
parabolic dishes. The new approach of simultaneous considering of exergy destruction rate and exergy
efficiency is used to analyze the system, which results in lower energy consumption and higher exergy
efficiency. Accordingly, the COP of the plant is calculated as 0.2002 and it consumes 4.02 kWh/kgLH2
thatis 8.93 percent less than the basic liquefier. Moreover, the overall exergy efficiency of it is 73.57% is
24.60% more than the basic system one. As well as, results indicate that the cryogenic sector of the
process consumes 73% of the total consumed energy. Furthermore, exergy analysis shows that the most
exergy destruction occurs in the solar collectors (43.59%) and heat exchangers (40.23%), and when the
exergy efficiency varies 1.9% during a typical day, the exergy destruction change will be 9.5%. As well as,
sensitive analysis shows that when solar energy increases by 204% due to adding more solar collectors,
boilers energy decreases by 59%. Moreover, when the number of the collectors doubles, the production
rates and the energy consumption of the process are also doubled. However, more power will be needed
that will increase the operating cost of the liquefier. Therefore, an exergy-economy analysis may be used
to address the optimum solutions.
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