Multi-objective optimization of two hybrid power generation systems for optimum selection of SOFC reactants heat exchangers mid-temperatures

Increasing effciency and decreasing cost are the main purposes in the design of 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 thermodynamics improvement in the hybrid system operation. For this purpose, using two sets of SOFC reactant heat exchangers (primary heat exchangers and secondary heat exchangers) are recommended. Selection of the primary heat exchangers output temperature and therefore the secondary heat exchangers input temperature (heat exchangers mid-temperatures) in uences the thermodynamics and economics operation of the hybrid system. This work shows that the annualized cost (ANC) and the levelized cost of energy (LCOE) act in con ict with each other. MatLab genetic optimization algorithms are used to obtain the optimum solutions. The maximum achievable eff ciency is 0.599 and the minimum LCOE is 0.0163 $/kWh. Also, results show that the heat exchangers mid-temperature of air plays the main role in the operation of the hybrid system.