Energy technology最新文献

Dear readers,

With the adoption of the National Hydrogen Strategy (NWS) in June 2020 and its update in July 2023, the German government strengthens the establishment of a hydrogen economy in Germany to achieve the Paris climate goals and to build an energy system based on renewable energies.

To meet the required demand international imports will complement the national production. Supra-regional storage and transport infrastructures for green hydrogen are needed to ensure efficient temporal and spatial distribution.

This is where TransHyDE comes in as one of three hydrogen flagship projects funded by the German Federal Ministry of Education and Research (BMBF). The project is coordinated by Prof. Robert Schlögl (Max Planck Society), Prof. Mario Ragwitz (Fraunhofer Institute for Energy Infrastructures and Geothermal Energy IEG) and Jimmie M. Langham (cruh21 GmbH - Part of Drees & Sommer).

Over 100 partners and associated partners are working to resolve technological and economic barriers, analyse gaps in technical codes and regulatory frameworks, and contribute to closing them. This is implemented by ten TransHyDE projects for the energy vectors gaseous and liquid hydrogen as well as liquid organic hydrogen carriers (LOHC) and ammonia. The results are continuously communicated via target-specific measures, e. g. whitepapers, scientific papers and events, to the scientific community, political decision-makers and the general public.

This special issue of the scientific journal Energy Technology mirrors the comprehensive thematical set-up of the TransHyDE projects by illustrating their aspects of the transport and storage infrastructure of hydrogen and its derivates. The perspectives of the featured articles and reviews are remarkably diverse and span the full range from higher level topics like transitioning paths towards climate neutral gas grids to providing answers to specific, in-depth technological questions that need to be solved to make the models become reality. The technology-open approach of TransHyDE is clearly visible in this special issue as it is not limited to one specific hydrogen transport option or infrastructural component, where for example hydrogen storage with LOHC technology, as well as underground storage in sandstone formations and the direct usage of ammonia in combustion engines are examined next to one another. Studies on public acceptance and societal risk perception add to the technological perspectives and allow putting them into action.

With this broad range of topics, the TransHyDE special issue invites readers to take a holistic approach to future transport and storage infrastructure of hydrogen and its derivates in Germany. We firmly believe that only by putting all our knowledge together and remaining technology-open we will be able to find efficient solutions to sensibly conclude the ongoing energy transition.

Performance degradation in solid oxide fuel cells (SOFCs) leads to shorter service life and unexpected downtime. To reduce economic losses and accelerate commercialization, accurately predicting the degradation is conducted in this study. First, a comprehensive analysis of performance degradation through experiments on a real SOFC system is investigated. Then, three dada-driven robust models, that is, vector autoregressive moving average (VARMA), radial basis function neural network (RBFNN), and neural basis expansion analysis for time series (N-BEATS) models are proposed to predict the SOFC's performance degradation. Herein, the top 60–90% of the experimental datasets are used for training and the bottom 40–10% for testing. After training, the prediction performance testing of these 3 models is compared with that of the bi-long short-term memory networks (bi-LSTM) and bi-gated recurrent units (bi-GRU) models. Simulation results show that both the VARMA and N-BEATS models are superior to the bi-LSTM and bi-GRU models in predicting the performance degradation of the SOFC. While the test performance of the RBFNN model is worst, especially under the top 60% training datasets condition. These indicate it is feasible to respectively establish the VARMA model and the N-BEATS model for predicting the SOFC's performance degradation.

In the cement industry, much waste heat is released into the environment. The organic Rankine cycle is widely utilized to harness waste heat for power generation. However, significant energy is lost in the heat recovery process due to the finite temperature difference between the heat source and working fluid, resulting in low power output andefficiency. To enhance the heat recovery from the cement flue gas and increase power output and overall efficiency, a novel partial evaporating cycle with ejector is proposed and investigated in this study. Pinch point analysis is performed to characterize the heat recovery process in the evaporator. The effects of the evaporating temperature, outlet quality of the evaporator, and exit pressure of the primary expander on system performance are also investigated. Results show that partially evaporating the fluid improves heat matching and reduces the irreversibilities in the evaporator by up to 18.1% when the outlet quality of the fluid is 0.33. Maximum net power of 803.15 kW can be generated with an evaporating temperature of $��130�\hspace{0.17em}°�C�$, outlet quality of 0.33, and expander exit pressure of 1054.9 kPa. Additionally, the inclusion of the ejector increases the net power produced by up to 76.07 kW.

CuFe₂O₄, an iron-based spinel catalyst, along with NiFe₂O₄, CoFe₂O₄, MgFe₂O₄, CeFe₂O₄, and MnFe₂O₄ are prepared using the sol–gel method. Different modified transition metals have been investigated to determine the influence on hydrogen production in a fixed-bed reactor. The results indicated that all the prepared catalysts exhibit a spinel structure. At a reaction temperature of 700 °C, with a water–carbon molar ratio of S/C = 1.5 and a biomass-to-catalyst mass ratio of 1:1, the performance ranking of the AFe₂O₄ spinel catalysts is as follows: CeFe₂O₄ > CuFe₂O₄ > MnFe₂O₄ > NiFe₂O₄ > CoFe₂O₄ > MgFe₂O₄ > no catalyst. CeFe₂O₄ and CuFe₂O₄ catalysts demonstrate superior performance, with hydrogen volume fractions of 42.26% and 41.63% respectively. The AFe₂O₄ catalyst exhibits effective catalytic activity in the production of hydrogen from corn straw using water vapor, with the synergistic effect of A metal and Fe enhancing the catalytic activity of AFe₂O₄.

Recent advances in solar cell technology have been motivated by new materials and inventive engineering techniques. Dye-sensitized solar cells (DSSCs) are becoming more widely recognized as a possible alternative for sustainable energy. Optimizing electrolytes is one of the most important variables impacting their effectiveness and durability. The electrolyte interface is critical to optimize charge separation, ion transport, and diffusion ensuring device stability and efficiency. The present investigation focuses on enhancing interface stability and investigating innovative electrolyte compositions to improve DSSC performance for sustainability in solar energy applications. Despite progress, obstacles remain in presenting core principles and research approaches in DSSC technology. Continued research is required to overcome these limitations and fully realize the potential of DSSCs in sustainable energy solutions.

The development of efficient, low-cost, non-noble metal-oxide-based nanohybrid materials for overall water splitting is a critical strategy for enhancing clean energy use and addressing environmental issues. In this study, an interfacial engineering strategy for the development of bimetallic Co–Ni nanoparticles on graphitic carbon nitride (g-C₃N₄) using ultrasonication followed by coprecipitation is conveyed. These nanoparticles demonstrate high efficacy as bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline conditions. Co–Ni nanoparticles on graphitic carbon nitride demonstrate an increased surface area via ultrasonication and subsequent coprecipitation. The g-C₃N₄ combined with Co–Ni nanoparticles leads to the development of bifunctional catalysts that exhibit significant efficiency in both HER and OER, and their interfacial properties are investigated for the first time. The chemical composition and morphology of g-C₃N₄ integrated with Co–Ni nanoparticles significantly influence the modulation of redox-active sites and the facilitation of electron transfer, resulting in improved splitting efficiency. The interactions between the Co–Ni bimetal and g-C₃N₄ demonstrate exceptional electrochemical performance for water splitting. Consequently, the 20% 20–Co–Ni–graphitic carbon nitride electrode demonstrated superior HER performance, comparable to the other electrodes. In the results, it is indicated that an increased molar ratio of Co and Ni incorporated in graphitic carbon nitride significantly improves HER performance.

The deposition of amorphous hydrogenated silicon nitride (a-SiN_x:H) via plasma-enhanced chemical vapor deposition is critical for optimizing the performance of crystalline silicon (c-Si) solar cells. This study investigates the impact of varying gas ratios (GR = NH₃/SiH₄) on the optical and physical properties of deposited SiN_x films. Results show that the refractive index (RI) ranges from 1.8 to 2.3 with changing gas compositions. Fourier transform infrared Spectroscopy reveals shifts in [SiNH] and [SiH] stretching modes, indicating changes in hydrogen passivation and nitrogen incorporation. Hydrogen bonding densities of [SiH] and [SiNH] correlate positively with the RI. For example, the hydrogen bonding density [N_H] ranges from 4.53 × 10²³ to 6.32 × 10²³ cm⁻³ for [SiNH] bonds while [Si-H] varies from 6.93 × 10²³ to 1.06 × 10²⁴ cm⁻³. Secondary ion mass spectrometry (SIMS) analysis shows stable hydrogen intensity, contrasting with a decrease in nitrogenhydrogen bonds. These findings highlight the key role of hydrogen bonding in determining SiN_x film properties, with significant implications for semiconductor and photovoltaic applications.

The nanofluids are the potential substitute in solar collectors as working fluids for better photothermal conversion efficiency. The present investigation focuses on the development of aqueous-based nanofluids comprising multiwalled carbon nanotubes (MWCNTs) with and without surfactants to enhance the capacity of photothermal conversion in direct absorption solar collectors. To improve the stability of the nanofluid, the gum Arabic (GA) and polyvinyl alcohol (PVA) are used as the surfactants. The stable nanofluid was characterized using UV-visible spectroscopy, zeta potential, fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy (EDS) analysis. The results indicated that the thermal conductivity was enhanced by 94.57% and 91.19% for the MWCNT/GA/deionized (DI) water and MWCNTs/PVA/DI water based nanofluids in presence of surfactants at 90 °C and 0.02 wt%. The presence of surfactant in MWCNTs/DI water nanofluids exhibit excellent stability and enhanced MWCNTs dispersion. In the photothermal response analysis, the highest temperature of 62.8 °C, which is 16 °C higher than the base fluid, is obtained from 0.02wt% MWCNT/GA nanofluid. The highest efficiency of 27.94% is recorded when 0.02wt% MWCNT/GA nanofluid is used, which shows 71.24% enhancement as compared to the DI water after exposure of 30 minutes under solar irradiation. The use of MWCNTs/GA nanofluid as light-absorbing working fluids in solar collectors is encouraged in the present investigation.