Thermodynamic study of the effect of partial thermal reduction of dysprosium oxide on solar-to-fuel energy conversion efficiency

Abstract

A thermodynamic equilibrium and efficiency analysis of the dysprosium oxide-based solar thermochemical H2O splitting (Dy-WS) cycle is conducted. The objective of this study is to understand the effect of partial thermal reduction (TR) of Dy2O3 on the solar-to-fuel energy conversion efficiency (ηsolar-to-fuel-Dy-WS) of the Dy-WS cycle. The equilibrium analysis indicate a rise in the percentage TR of Dy2O3 (%TR-Dy) from 0.3% up to 100% when the TR temperature (TH) is increased from 2000 K to 2530 K. The upsurge in the TH yielded a considerable surge in the Q̇solar-reactor-Dy-WS and Q̇solar-heater-Dy-WS. Overall results of this study showed that the ηsolar-to-fuel-Dy-WS is amplified from 0.6% to 6.5% in three zones (slow zone, medium-fast zone, and fast zone) as the TH is amplified from 2000 K up to 2280 K. A further rise in the TH from 2280 K up to 2530 K resulted in a drop in the ηsolar-to-fuel-Dy-WS from 6.5% to 3.5%. By employing the heat recuperation, the ηsolar-to-fuel-HR-Dy-WS is improved further up to 11.4% (at TH = 2280 K).