International Journal of Hydrogen Energy, Vol.45, No.10, 5816-5828, 2020
A novel three-step GeO2/GeO thermochemical, water splitting cycle for solar hydrogen production
This investigation reports the thermodynamic exploration of a novel three -step GeO2/GeO water splitting (WS) cycle. The thermodynamic computations were performed by using the data obtained from HSC Chemistry thermodynamic software. Numerous process parameters allied with the Ge02/GeO WS cycle were estimated by drifting the thermal reduction (TN) and water splitting temperature (TL). The entire analysis was divided into two section: a) equilibrium analysis and b) efficiency analysis. The equilibrium analysis was useful to determine the TN and TL required for the initiation of the thermal reduction (TR) of GeO2 and re -oxidation of GeO via WS reaction. Furthermore, the influence of PO2 on the TN required for the comprehensive dissociation of GeO2 into GeO and O-2 was also studied. The efficiency analysis was conducted by drifting the TH and TL in the range of 2080 to 1280 K and 500-1000 K, respectively. Obtained results indicate that the minimum Cisolar-cycle = 624.3 kW and maximum solar-to fuel = 45.7% in case of the GeO2/GeO WS cycle can be attained when the TR of Ge02 was carried out at 1280 K and the WS reaction was performed at 1000 K. This ']solar-to-fuel = 45.7% was observed to be higher than the SnO2/SnO WS cycle (39.3%) and lower than the ZnO/Zn WS cycle (49.3%). The Cisolar-cycle can be further decreased to 463.9 kW and the (solar-to-fuel can be upsurged up to 61.5% by applying 50% heat recuperation. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.