Optimum selection of the heat exchangers mid-temperatures for SOFC reactants in a hybrid system

Increasing efficiency and decreasing cost are the main pul‘[)0SCS in the design of the power generation systems. In this study two hybrid systems: solid oxide fuel cell (SOFC)-gas turbine (GT) and SOFC-GT- steam turbine (ST); are considered. Increasing the SOFC input temperature causes thennodynamics improvement in the hybrid system operation. For this purpose, using two set of SOFC reactants heat exchangers (primary heat exchangers and secondary heat exchangers) are recommended. Selection of Theprimary heat exchangers output temperature and therefore the secondary heat exchangers input temperature (heat exchangers mid-temperatures) influences 011 the thermodynamics and economics operation of the hybrid system. This work shows that the aimualized cost (ANC) and the levelized cost of energy (LCOE) act in conflict with each other. The MatLab genetic optimization algorithms are used to obtain the optimum solutions. The maximum achievable efficiency is 0.599. Also results show thatthe heat exchangers inid-temperature of air has the main role in the operation of the hybrid system.

Keywords:

heat exchanger , SOFC , gas turbine , steam turbine: multi-objective optimization