Prof. Abraham Kribus
School of Mechanical Engineering, Tel Aviv University, Israel

Biography: Dr. KRIBUS is a Professor of Mechanical Engineering at Tel Aviv University. He has a B.Sc. in Mechanical Engineering from Tel Aviv University, and a Ph.D. in Mechanical and Aerospace Engineering (1991) at Cornell University. He worked at the Weizmann Institute of Science in Israel on high temperature solar thermal conversion, including optics, heat transfer and thermodynamics. He joined the Faculty of Engineering at Tel Aviv University in 2001. Since then he has been working on research of solar thermal, photovoltaic and thermionic conversion; thermodynamic and thermo-chemical cycles; and thermal energy storage. He has consulted for many solar energy companies, co-founded a solar energy startup in Israel, and served as Chief Technologist at eSolar (USA). Prof. Kribus has served as head of the Department of Fluid Mechanics, head of the M.Sc. program in Environmental Studies, Associate Editor of leading solar energy journals, and Chairman of the Israel Section of the International Solar Energy Society (ISES). He has published over 240 journal and conference publications, as well as 8 patents.

Speech title: Solar electricity generation and storage with thermally recharged flow batteries

Abstract: A novel concept is presentedfor solar electricity generation and storage, based on thermal regeneration (charging) of flow batteries. Concentrated sunlight is used for external thermo-chemical charging of a flow battery, while electricity is produced by conventional electro-chemical discharge of the battery. This approach employs the concentrator technologies of thermo-solar plants (e.g., solar tower), but eliminates the thermo-mechanical conversion step (turbine) and the multiple fluid circuits (only a single working fluid is used). The thermo-electro-chemical storage (TECS) concept offers potential performance, cost and operational advantages compared to existing solar technologies, and compared to existing storage solutions for management of an electrical grid with a significant contribution of intermittent solar electricity generation. Analysis of the theoretical conversion efficiency was performed for TECS plant schemes based on the electro-chemical systems of sodium-sulfur and zinc-air. The thermodynamic upper limit (ideal system) for solar to electricity conversion efficiency is 60%-65% for both systems, with required reactor temperature of >1550 K and sunlight concentration of 3000. A hybrid process with carbothermic reduction in the zinc-air system reaches 60% theoretical efficiency at the more practical conditions of reaction temperature <1200 K and concentration <1000. These upper limits are very promising compared to existing solar electricity technologies.Practical TECS cycles with more realistic models of component losses, and the technical feasibility of the proposed cycle, will also be discussed.