Innovative solar thermochemical water splitting.

Hogan, Roy E. Jr. ; Siegel, Nathan P. ; Evans, Lindsey R. ; Moss, Timothy A. ; Stuecker, John Nicholas (Robocasting Enterprises, Albuquerque, NM) ; Diver, Richard B., Jr. ; Miller, James Edward ; Allendorf, Mark D. (Sandia National Laboratories, Livermore, CA)

关键词: CONSTRUCTION;    COUNTER CURRENT;    DESIGN;    EFFICIENCY;    FERRITE;    FERRITES;    HEAT ENGINES;    HYDROGEN;    IRON OXIDES;    OXIDES;    OXYGEN;    SANDIA NATIONAL LABORATORIES;    SOLAR FLUX;    THERMAL EFFICIENCY;    THERMODYNAMICS;    WATER Solar thermal energy.;    Thermochemical properties.;    Water chemistry.;   

DOI  :  10.2172/932876
RP-ID  :  SAND2008-0878
PID  :  OSTI ID: 932876
Others  :  TRN: US200814%%777

学科分类：再生能源与代替技术

美国|英语

来源: SciTech Connect

【 摘 要 】

Sandia National Laboratories (SNL) is evaluating the potential of an innovative approach for splitting water into hydrogen and oxygen using two-step thermochemical cycles. Thermochemical cycles are heat engines that utilize high-temperature heat to produce chemical work. Like their mechanical work-producing counterparts, their efficiency depends on operating temperature and on the irreversibility of their internal processes. With this in mind, we have invented innovative design concepts for two-step solar-driven thermochemical heat engines based on iron oxide and iron oxide mixed with other metal oxides (ferrites). The design concepts utilize two sets of moving beds of ferrite reactant material in close proximity and moving in opposite directions to overcome a major impediment to achieving high efficiency--thermal recuperation between solids in efficient counter-current arrangements. They also provide inherent separation of the product hydrogen and oxygen and are an excellent match with high-concentration solar flux. However, they also impose unique requirements on the ferrite reactants and materials of construction as well as an understanding of the chemical and cycle thermodynamics. In this report the Counter-Rotating-Ring Receiver/Reactor/Recuperator (CR5) solar thermochemical heat engine and its basic operating principals are described. Preliminary thermal efficiency estimates are presented and discussed. Our ferrite reactant material development activities, thermodynamic studies, test results, and prototype hardware development are also presented.