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Research Abstracts Online
January 2008 - March 2009

University of Minnesota Twin Cities
Institute of Technology
Department of Mechanical Engineering

PI: Jane H. Davidson, Associate Fellow

Design of a Quench Device for Synthesis and Hydrolysis of Zn Nanoparticles; Development of a Liquid Desiccant Solar Thermal and Chemical Energy Storage

These researchers have been involved in two projects during this period. In the first, they are evaluating a new tubular reactor for the synthesis and hydrolysis of zinc nanoparticles. A key component of the reactor is a quench ring that achieves a rapid argon/steam quench of zinc gas to form an aerosol of zinc oxide nanoparticles. The quench ring is comprised of three co-axial and multi-inlet confined jets that exit to a quartz tubular reactor. A mixture of zinc gas and argon at 900 K flows through a 4 mm diameter round inlet at the center of the ring. The zinc is quenched and hydrolyzed as it mixes with argon and steam fed through two concentric arrays of 1 mm diameter holes. Computational fluid dynamic modeling of the reactor shows the impact of varying flow rates on temperature and velocity distributions.

In the second project, the researchers are developing a scaled prototype vessel filled with an aqueous salt liquid desiccant for seasonal residential solar energy storage. Chemical energy is stored using the low chemical potential of 0.55 wt.% CaCl2 solution. Dilution of the solution with water or less concentrated aqueous CaCl2 converts the chemical energy to heat. The solution properties are a strong function of concentration. Density changes with concentration overwhelm density changes due to temperature that typically allow thermal stratification and natural convection in conventional solar thermal energy storage. Numerical simulation of internal processes including buoyant jets, surface condensation, and density stratification will aid in the development of mixing rules and an engineering model for the new storage.

Group Members

Aiman Alshare, Research Associate
Marc Brulhart, Visiting Researcher
Julia Haltiwanger, Graduate Student
Brandon Hathaway, Graduate Student
Gur Mittelman, Research Associate
Josh Quinnell, Graduate Student
Luke Venstrom, Graduate Student