Multi-objective optimization of the hydrogen fuel production of a solar-based cobalt-chlorine (Co–Cl) thermochemical cycle with grey relational analysis.

In this paper, multi-objective optimization of the hydrogen production ( m ˙ H 2 ) of a solar-based cobalt-chlorine (Co–Cl) thermochemical cycle with grey relational analysis (GRA) has been performed. Monthly total irradiance averages (A), wind velocity (B), receiver height (C), receiver radius (D) and number of heliostats (E) are considered to achieve the highest the useful energy absorbed by the solar receiver ( Q ˙ a b s ), efficiency of the receiver (η r e c ), the overall efficiency of the system (η o v e r a l l) and hydrogen production ( m ˙ H 2 ). Orthogonal experimental design is planned according to L 18 orthogonal array created by Taguchi method. The percent contribution rates (PCR) on the Q ˙ a b s , η r e c , η o v e r a l l and m ˙ H 2 are determined with the help of ANOVA analysis. The optimal parameters are identified as monthly total irradiance average of 143.8 kW h (A 3), wind velocity of 5 m/s (B 2), receiver height of 8 m (C 1), receiver radius of 3 m (D 1) and number of heliostats of 850 (E 3), respectively. The highest Q ˙ a b s , η r e c , η o v e r a l l and m ˙ H 2 values corresponding to A 3 B 2 C 1 D 1 E 3 are obtained as 50.2 GW; 64.1%; 22.2% and 122.59 (tons/month), respectively. The PCR of the A, B, C, D and E parameters influencing the f-factor are determined to be 12.6 %, 1.92 %, 0.48 %, 15.03 %, and 53.20 %, respectively. Also, empirical equations are developed with regression analysis (RA) to estimate the Q ˙ a b s , η r e c , η o v e r a l l , m ˙ H 2 values. The statistical coefficients (R2-value) for training and testing data's are determined in the range of 0.771167–0.99608 for Q ˙ a b s , η r e c , η o v e r a l l and m ˙ H 2 , respectively. • Hydrogen production of a solar-based Co–Cl has been investigated. • Optimization of solar-based Co–Cl determined with Taguchi based GRA. • The η o v e r a l l of solar-based Co–Cl computed as 22.2%. [ABSTRACT FROM AUTHOR]