As different liquid desiccants show different dehumidification and operation characteristics, the comprehensive performance comparison between two liquid desiccants (LiCl and LiBr aqueous solutions) was conducted in this paper. The electronic conductivity of the LiBr aqueous solution was experimentally investigated and the electronic conductivity model of the LiBr solution was acquired. Compared with the LiCl solution, the LiBr solution has higher electronic conductivity within the concentration range of 20–40% and the temperature range of 20–60 °C, which means the ED regenerator using LiBr solution has lower electric resistance. The increase of the liquid desiccant concentration is beneficial to the moisture removal rate but harmful to the whole system COP and dehumidification efficiency, while the effect of the liquid desiccant temperature is opposite. Within the liquid desiccant temperature range of 20–30 °C, the whole system COP varies among 1 and 2.8 for the LiCl solution with the concentration of 38% at the exit of the ED regenerator, and it is among 2.5 and 5.8 for the LiBr solution with the concentration of 55% after regeneration. Using the LiCl solution can give the system the better dehumidification potential, while using LiBr solution can help the system to acquire the better whole performance and economy.
The protonic ceramic fuel cells (PCFCs) can convert the chemical energy of fuel directly into electric power, with the advantages of high efficiency and alternative fuel range at intermediate temperatures. Ammonia has been regarded as a promising fuel for PCFCs due to its carbon-free and hydrogen-rich properties, high volumetric energy density and easy storage/transportation. However, the performance of ammonia PCFCs (NH 3 -PCFCs) is far inferior to the hydrogen PCFCs (H 2 -PCFCs) because of the sluggish and complex kinetics at anodes. In this study, we established an elementary reaction kinetic model for NH 3 -PCFCs, investigated the effect of reaction parameters, anode components and reaction partition, and explored the coupling mechanism between the ammonia decomposition and electrochemical reaction. Importantly, the ammonia decomposition and electrochemical reaction can be flexibly regulated by adjusting anode parameters, then affecting the performance ratio of NH 3 -PCFCs and H 2 -PCFCs. The detailed rate-determining steps were further identified by experimental and model analysis. Thus, the ammonia/hydrogen performance ratio of the cell can exceed 95% at 550°C after accelerating the ammonia decomposition reaction. Our work provides insights into the kinetics in NH 3 -PCFCs for improving their performance with optimization.
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