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Emerging energy storage systems based on abundant and cost-effective materials are key to overcome the global energy and climate crisis of the 21st century.

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Abstract Experimental and theoretical investigations have been performed on critical heat flux ( CHF ) and turbulent mixing in tight, hexagonal, 7-rod bundles. Freon-12 was used as working fluid due to its low latent heat, low critical pressure and well known properties. It has been found that the two-phase mixing coefficient depends mainly on mass flux. It increases with decreasing mass flux and ranges from 0.01 to 0.04 for the test conditions considered. More than 900 CHF data points have been obtained in a large range of parameters: pressure 1.0–3.0 MPa and mass flux 1.0–6.0 Mg/m 2 s. The effect of different parameters on CHF has been analysed. It has been found that the effect of pressure, mass flux and vapour quality on CHF is similar to that observed in circular tubes. Nevertheless, the CHF in the tight rod bundle is much lower than that in a circular tube of the same equivalent hydraulic diameters. The effect of wire wraps on CHF is mainly dependent on local vapour qualities and subsequently on flow regimes. Based on subchannel flow conditions, the effect of radial power distribution on CHF is small. Comparison of the test results with CHF prediction methods underlines the need for further work.

AbstractAmine based solvent used for CO2 capture can be lost during the process due to: degradation, vaporization, mechanical losses and aerosol (mist) formation. Only recently, studies have appeared pointing out that aerosols can dominate the total amine emission at pilot plant scale behind coal fired power plants. Future full scale amine scrubber installations will be imposed emission limit values (ELV) for a number of components including NH3 and the amine itself. Most likely these ELV will be expressed as maximum concentrations tolerated in the CO2 poor flue gas leaving the stack so it is important to prevent or cure amine aerosol emission. The study presents a novel combination of two existing measurement techniques, that measure: (i) amine emissions from the top of the absorber using FTIR and (ii) PSD of the incoming flue gas using the ELPI+. The study is the first to show how combining these two measurement techniques allows to predict the presence or absence of mist formation. This hypothesis is based on information obtained during several measurement campaigns on different pilot plants.

Hydrodeoxygenation (HDO) of bio-oils obtained from intermediate pyrolysis with hot vapor filtration was investigated over Ru/C and NiCu/Al2O3 catalysts as a function of several parameters: feedstock (beech wood, wheat straw), pyrolysis temperature, catalyst and hydrotreatment temperature. Beech wood was found to be a suitable feedstock for HDO due to its low heteroatom content, whereas the high sulfur content in the wheat straw bio-oil caused irreversible poisoning of the catalysts. Ru/C generally consumed more hydrogen than NiCu/Al2O3, showing higher hydrogenation/HDO activity with higher selectivity towards alcohols and hydrocarbons, whereas NiCu/Al2O3 resulted in a higher concentration of ketones. The pyrolysis temperature affected the fragmentation degree; higher temperatures resulted in a higher quality pyrolysis oil with low oxygen mass fraction, but with decreased mass yield. By varying the hydrotreatment temperature (80, 150, 250, 350 °C), different classes of compounds were converted and different deoxygenation degrees were achieved. Overall the results indicate that intermediate pyrolysis with hot vapor filtration is a valid alternative to the more commonly used fast pyrolysis for decentralized (or small-scale) applications, especially for heterogeneous feedstocks with high ash content.

AbstractFor future integration into building facades or overhead glazing, the direct deposition of organic solar modules on glass substrates in sheet‐to‐sheet processes may be more cost efficient than postproduction lamination. Complying with the special requirements for the deposition of the layer stack on glass substrates, we report on all‐doctor‐bladed organic solar modules yielding power conversion efficiencies of 4.5 and 3.6 % on photoactive areas of 1 and 20 cm2, respectively. The bottom electrode is doctor bladed from a silver ink atop an adhesion enhancing primer. The top electrode is applied from silver nanowires, dispersed in poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), which thereby avoids any visible bus bars and reduces shading of the active layer. Importantly, all layers are deposited under ambient conditions by using only non‐chlorinated, eco‐compatible solvents.

High He/dpa microstructural effects have been investigated, by means of small-angle neutron scattering (SANS) and transmission electron microscopy (TEM), in B-alloyed ferritic/martensitic steel Eurofer97-1 (0.12 C, 9 Cr, 0.2 V, 1.08 W wt%, B contents variable between 10 and 10 0 0 ppm), neutron irradiated at the High Flux Reactor of the JRC-Petten at temperatures between 250 °C and 450 °C, up do a dose level of 16 dpa. Under these irradiation parameters, B activation is expected to produce corresponding helium contents variable between 80 and 5600 appm, with helium bubble distributions relevant for the techno- logical applications. The SANS measurements were carried out under magnetic field to separate nuclear and magnetic SANS components; a reference, un-irradiated sample was also measured to evaluate as accurately as possible the genuine effect of the irradiation on the microstructure. Increasing the esti- mated helium content from 400 to 5600 appm, the analysis of the SANS cross-sections yields an increase in the volume fraction, attributed to helium bubbles, of almost one order of magnitude (from 0.007 to 0.038); furthermore, the difference between nuclear and magnetic SANS components is strongly reduced. These results are discussed in correlation with TEM observations of the same samples and are tentatively attributed to the effect of drastic microstructural changes in Eurofer97-1 for high He/dpa ratio values, possibly relating to the dissolution of large B-carbides due to transmutation reactions.

Fast charging infrastructure is widely acknowledged as necessary for the market success of electric vehicles. However, fast charging requires cost intensive infrastructure and grid connections. Accordingly, the risk of sunk cost is high, although fast charging infrastructure might be profitable in the medium to long term. In addition, the demand for fast charging varies greatly and the maximum power of charging stations may only be needed for a short time period per week. Although the profitability of stationary storages and the demand for fast charging have gained broad attention in literature, the specific question of how and under what circumstances stationary batteries can increase the profitability of fast charging stations has not yet been addressed for all potential applications. Here, we analyze the extent to which stationary storages can increase the profitability of fast charging stations by reduced grid connection costs on the one hand and additional revenues from intraday trading of electricity on the other hand. We compare different battery technologies and distinguish two use cases: fast charging in cities and along highways. Our results indicate that the profitability of a stationary storage installed together with a fast charging station depends on various parameters. While for a city fast charging station, intraday trading might lead to lower cost, this is not the case for highway stations since the heavy use motivated by intraday trading can significantly shorten battery life. Our results underline the importance of second life batteries since low-cost batteries have a significant impact on the system’s profitability.

An aluminium battery using an organic redox polymer as a positive electrode material delivers high reversible specific capacities at fast C-rates.