Name: Joseph Baker
Title: ANALYSIS OF MASS TRANSFER IN ELECTROCHEMICAL MEMBRANE PUMPING DEVICES
Professor Reinhard Radermacher, Chair
Research Professor Yunho Hwang, Co-Chair
Professor Chunsheng Wang
Associate Professor Katrina Groth
Professor Bao Yang
Professor Peter Sunderland, Dean’s Representative
Date: Thursday, May 12th, 2022
Location: CEEE conference room, 088-4164B
Zoom Link: https://umd.zoom.us/j/2448374295
Considering the environmental challenges posed by traditional energy systems, we must strive to
seek out innovative strategies to sustainably meet today’s demands for energy and quality of life.
Energy systems using electrochemical (EC) energy conversion methods may help us to transition
to a more sustainable energy future by providing intermittent renewable energy storage and
improving building energy efficiency. EC pumping devices are a novel technology that use
chemical reactions to pump, compress, or separate a given working fluid. These devices operate
without any moving parts. Unlike mechanical pumps and compressors, they operate silently,
producing no vibrations and requiring no lubrication. In this dissertation, I examine the
applicability for EC pumping devices in energy storage via compressed ammonia and in
dehumidification for air conditioning.
Hydrogen fuel cells are a promising technology for on-demand renewable power generation.
While storage of pure hydrogen fuel remains a problem, ammonia is an excellent hydrogen
carrier with far less demanding storage requirements. EC ammonia compression opens the door
to several possibilities for separating, compressing, and storing ammonia for intermittent power
generation. Using the same proton exchange membranes commonly used in fuel cells, I
demonstrated successful ammonia compression under a variety of operating conditions. I
examined the performance of a small-scale ammonia EC compressor, measuring the compression
and separation performance. I also conducted experiments to investigate the steady-state
performance of a multi-cell ammonia EC compressor stack, observing a maximum isothermal
efficiency of 40% while compressing from 175 kPa to 1,000 kPa. However, back diffusion of
ammonia reduced the amount of effluent ammonia by as much as 67%.
Dehumidification represents a significant portion of air conditioning energy requirements.
Separate sensible and latent cooling using EC separation of water may provide an energy
efficient thermal comfort solution for the hot and humid parts of the world. I conducted
experiments of several EC dehumidifier, considering both proton exchange and anion exchange
processes. Diffusion of the working fluid was significant in this application as well. I observed a
maximum Faradaic efficiency for dehumidification of 40% for a 50 cm2 cell using an anion
exchange membrane under the most favorable case. I developed a novel open-air EC
dehumidifier prototype. To alleviate the back diffusion issue, I investigated a method for mass
transfer enhancement using high-voltage fields. I also developed a numerical model to simulate
the performance of the EC dehumidifier devices, predicting the experimentally measured
performance to within 25%.