Exergoeconomic analysis of a thermochemical copper-chlorine cycle for hydrogen production using specific exergy cost (SPECO) method

The manner is investigated in which exergy-related parameters can be used to minimize the cost of a copper-chlorine (Cu-Cl) thermochemical cycle for hydrogen production. The iterative optimization technique presented requires a minimum of available data and provides effective assistance in optimizing thermal systems, particularly in dealing with complex systems and/or cases where conventional optimization techniques cannot be applied. The principles of thermoeconomics, as embodied in the specific exergy cost (SPECO) method, are used here to determine changes in the design parameters of the cycle that improve the cost effectiveness of the overall system. The methodology provides a reasonable approach for improving the cost effectiveness of the Cu-Cl cycle, despite the fact that it is still in development. It is found that the cost rate of exergy destruction varies between $1 and $15 per kilogram of hydrogen and the exergoeconomic factor between 0.5 and 0.02 as the cost of hydrogen rises from $20 to $140 per GJ of hydrogen energy. The hydrogen cost is inversely related to the exergoeconomic factor, plant capacity and exergy efficiency. The results are expected to assist ongoing efforts to increase the economic viability and to reduce product Costs of potential commercial versions of this process. The impact of the results are anticipated to be significant since thermochemical water splitting with a copper-chlorine cycle is a promising process that could be linked with nuclear reactors to produce hydrogen with no greenhouse gases emissions, and thereby help mitigate numerous energy and environment concerns. (C) 2009 Elsevier B.V. All rights reserved.