Direct Thermoacoustic Cooling of Cryogenic Hydrogen

Washington State University, Pullman WA

Investigators

Abstract

To address climate change, Humanity must reduce reliance on fossil fuels and find alternative ways to generate energy for industry, transportation, and consumers. Hydrogen, when produced using renewable energy sources, is considered as one of the most promising fuels for the future, and does not emit harmful pollutants when reacting with oxygen. However, being the lightest element, hydrogen in the gaseous form requires large containers for storage and is considered impractical for many applications. Liquid hydrogen is a very attractive compact energy source, but it can exist only at very low temperatures. Current cooling techniques for both liquefaction and storage of hydrogen are rather inefficient. To help make the hydrogen economy viable, a potentially efficient novel acoustic method for coupled cooling-conversion of cryogenic hydrogen is explored of this project. The accompanying educational and outreach activities aim at improving engineering education by developing materials for energy-related courses, summer programs for K-12 students, professional short courses, and a textbook on cryogenic hydrogen systems. The necessary steps to prepare hydrogen for liquefaction and subsequent storage in the low energy state include cryogenic cooling and spin-conversion. These processes can be potentially combined by employing thermoacoustic heat pumping in a porous matrix which will also serve as a catalytic bed, accelerating conversion of flowing orthohydrogen into parahydrogen. The exploration of this combined process and associated thermal transport, fluid flow, quantum transitions, dynamic regimes, and system engineering constitutes the intellectual significance of the proposed research. Modeling efforts will include development of a reduced-order framework for analysis of thermoacoustic-catalytic systems for cooling cryogenic hydrogen and setting up high-fidelity computational simulations, while incorporating models from different scientific and technical areas. Experimental systems will be designed, built, and tested for analysis validation and practical demonstrations of novel methods for cooling cryogenic hydrogen. Results and products generated in this project will help establish methods for practical design of efficient cryogenic hydrogen-based energy systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.