LAUSR

Abstract The influence of the partial pressure of O2 ( P O 2 ) on the viability of the Ca-ferrite based solar thermochemical H2O splitting cycle was thermodynamically scrutinized. The thermodynamic parameters were estimated by maintaining a steady thermal reduction (TR) and water splitting (WS) temperature equal to 1800 K and 1200 K, respectively. The reduction in the P O 2 from 10−1 atm to 10−5 atm resulted in an improvement in the degree of non-stoichiometry (δ) associated with the Ca-ferrite from 0.172 to 0.720. Besides, a similar drop in the P O 2 increased the Q ˙ C a F e 2 O 4 − r e d − C F W S and Q ˙ H 2 O − h e a t i n g − C F W S by 222.4 kW and 43.1 kW, separately. An upsurge in both Q ˙ C a F e 2 O 4 − r e d − C F W S and Q ˙ H 2 O − h e a t i n g − C F W S significantly affected the Q ˙ s o l a r − c y c l e − C F W S , and it was enhanced from 382.5 kW to 704.8 kW when the P O 2 increased from 10−1 atm to 10−5 atm. Even though Q ˙ s o l a r − c y c l e − C F W S was enlarged, due to the augmentation in H2 production, η s o l a r − t o − f u e l − C F W S was escalated from 12.8% to 29.2% when the P O 2 was decreased from 10−1 atm to 10−5 atm. By employing heat recuperation, the maximum η s o l a r − t o − f u e l − H R − C F W S (61.1%) was recorded for P O 2 = 10 − 5 atm .