Energy Convertors under Dynamic Conditions
Key energy convertors in the context of energy transition are water electrolysers, fuel cells and batteries. The AC conditions are valuable for analysis and diagnosis of processes in these devises, but also for possible enhancement of their operation in terms of e.g. lower degradation, higher energy efficiency etc, which is addressed on an example of proton exchange membrane water electrolysis (PEMWE). Additionally, use of dynamic conditions is followed also in bioelectrosynthetic applications. Furthermore, use of nonelectrical inputs (like concentration) under dynamic conditions is introduced with possible application as an online diagnostic tool for polymer electrolyte fuel cells.
Proton exchange membrane water electrolysis (PEMWE) is a key technology for storing excess electrical energy produced by renewables in the form of hydrogen (Figure 1). To achieve high productivity of hydrogen, operation at high current density is necessary. However, for this operating condition, high performance losses appear. Currently, a significant part of voltage losses at high current densities is assigned to mass transfer resistances in the anode porous transport layer. In addition to the mass transport, ohmic and kinetic resistances are present in the system.
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Establishing a hydrogen economy is widely regarded by governmental institutions around the world as a key solution for reducing CO2 emissions. In this context, polymer electrolyte membrane fuel cells (PEMFCs) are the primary energy conversion technology for both mobile and stationary applications. However, deploying PEMFCs in such a critical role necessitates significant improvements in their durability. Prolonged use can subject PEMFCs to various faulty conditions, accelerating degradation mechanisms and significantly reducing their operational life and performance [1]. To mitigate these effects and maintain high efficiency over time, online diagnostic tools for continuous health monitoring of the cells are essential.
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Electroenzymatic processes leverage the high selectivity of enzymes as biocatalysts, coupled with the electrochemical regeneration of their cofactors [1-4]. This approach holds promise for developing new biotechnological processes for both fine and bulk chemical production. This project, part of the German Research Foundation's priority programme "Bioelectrochemical and Engineering Foundations for Establishing Electrobiotechnology for Biosynthesis - Power to Value-added Products (eBiotech) (SPP 2240)," addresses current bottlenecks in electroenzymatic processes, such as product scale, productivity, and the efficiency of cofactor regeneration.
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