This research paper introduces an avant-garde poly-input DC-DC converter (PIDC) meticulously engineered for cutting-edge energy storage and electric vehicle (EV) applications. The pioneering converter synergizes two primary power sources-solar energy and fuel cells-with an auxiliary backup source, an energy storage device battery (ESDB). The PIDC showcases a remarkable enhancement in conversion efficiency, achieving up to 96% compared to the conventional 85-90% efficiency of traditional converters. This substantial improvement is attained through an advanced control strategy, rigorously validated via MATLAB/Simulink simulations and real-time experimentation on a 100 W test bench model. Simulation results reveal that the PIDC sustains stable operation and superior efficiency across diverse load conditions, with a peak efficiency of 96% when the ESDB is disengaged and an efficiency spectrum of 91-95% during battery charging and discharging phases. Additionally, the integration of solar power curtails dependence on fuel cells by up to 40%, thereby augmenting overall system efficiency and sustainability. The PIDC's adaptability and enhanced performance render it highly suitable for a wide array of applications, including poly-input DC-DC conversion, energy storage management, and EV power systems. This innovative paradigm in power conversion and management is poised to significantly elevate the efficiency and reliability of energy storage and utilization in contemporary electric vehicles and renewable energy infrastructures.

• Klíčová slova
• Conversion efficiency, Electric vehicle (EV) applications, Energy storage, Poly-input DC–DC converter (PIDC), Renewable energy systems,
• Publikační typ
• časopisecké články MeSH

Measuring the efficiency of piezo energy harvesters (PEHs) according to the definition constitutes a challenging task. The power consumption is often established in a simplified manner, by ignoring the mechanical losses and focusing exclusively on the mechanical power of the PEH. Generally, the input power is calculated from the PEH's parameters. To improve the procedure, we have designed a method exploiting a measurement system that can directly establish the definition-based efficiency for different vibration amplitudes, frequencies, and resistance loads. Importantly, the parameters of the PEH need not be known. The input power is determined from the vibration source; therefore, the method is suitable for comparing different types of PEHs. The novel system exhibits a combined absolute uncertainty of less than 0.5% and allows quantifying the losses. The approach was tested with two commercially available PEHs, namely, a lead zirconate titanate (PZT) MIDE PPA-1011 and a polyvinylidene fluoride (PVDF) TE LDTM-028K. To facilitate comparison with the proposed efficiency, we calculated and measured the quantity also by using one of the standard options (simplified efficiency). The standard concept yields higher values, especially in PVDFs. The difference arises from the device's low stiffness, which produces high displacement that is proportional to the losses. Simultaneously, the insufficient stiffness markedly reduces the PEH's mechanical power. This effect cannot be detected via the standard techniques. We identified the main sources of loss in the damping of the movement by the surrounding air and thermal losses. The latter source is caused by internal and interlayer friction.

• Klíčová slova
• efficiency, efficiency measurement, energy harvesting, lead zirconate titanate (PZT), piezoelectric, piezoelectric ceramic, polyvinylidene fluoride (PVDF), power conversion, power flow,
• Publikační typ
• časopisecké články MeSH

Energy efficiency analysis provides a deeper understanding of non-renewable energy dependent cropping systems. In this study, we examined the crop yield and energy efficiency of facultative rainfed wheat (WW - winter wheat, WS - spring wheat) and mineral nitrogen (N) fertilization (0, 50, 100, 150, and 200 kg N ha-1) in two growing seasons 2019/20 and 2020/21 in Central Europe. WW out performed WS significantly overall (2019/20: +30.3 to +47.9 %; 2020/21: +18.9 to +37.3 %) in terms of energy efficiency indicators. The impact of N fertilization on energy efficiency was minimal, largely due to one dose application of mineral N fertilizer. The highest estimated net-energy output (NEO) was observed at 160.2 kg N ha-1, which may not sustainable for this pedo-climatic region due to potential N emissions risks. Zero N fertilization showed best performance in terms of energy use efficiency (EUE), energy intensity (EI), and energy productivity (EP). The ERG z-score, which combines NEO and EUE into a single bi-dimensional indicator, indicated an optimal N fertilization level of 72.0 kg N ha-1.

• Klíčová slova
• Energy efficiency analysis, Facultative wheat, Mineral N fertilization, Pannonian environment, Sowing date,
• Publikační typ
• časopisecké články MeSH

This review covers the recent advancements in selected emerging energy sectors, emphasising carbon emission neutrality and energy sustainability in the post-COVID-19 era. It benefited from the latest development reported in the Virtual Special Issue of ENERGY dedicated to the 6th International Conference on Low Carbon Asia and Beyond (ICLCA'20) and the 4th Sustainable Process Integration Laboratory Scientific Conference (SPIL'20). As nations bind together to tackle global climate change, one of the urgent needs is the energy sector's transition from fossil-fuel reliant to a more sustainable carbon-free solution. Recent progress shows that advancement in energy efficiency modelling of components and energy systems has greatly facilitated the development of more complex and efficient energy systems. The scope of energy system modelling can be based on temporal, spatial and technical resolutions. The emergence of novel materials such as MXene, metal-organic framework and flexible phase change materials have shown promising energy conversion efficiency. The integration of the internet of things (IoT) with an energy storage system and renewable energy supplies has led to the development of a smart energy system that effectively connects the power producer and end-users, thereby allowing more efficient management of energy flow and consumption. The future smart energy system has been redefined to include all energy sectors via a cross-sectoral integration approach, paving the way for the greater utilization of renewable energy. This review highlights that energy system efficiency and sustainability can be improved via innovations in smart energy systems, novel energy materials and low carbon technologies. Their impacts on the environment, resource availability and social well-being need to be holistically considered and supported by diverse solutions, in alignment with the sustainable development goal of Affordable and Clean Energy (SDG 7) and other related SDGs (1, 8, 9, 11,13,15 and 17), as put forth by the United Nations.

• Klíčová slova
• Emission neutrality, Energy efficiency, Energy sustainability, Novel material, Smart energy,
• Publikační typ
• časopisecké články MeSH

The effect of high emissivity coatings on the radiative heat transfer in steam cracking furnaces is far from understood. To start, there is a lack of experimental data describing the emissive properties of the materials encountered in steam cracking furnaces. Therefore, spectral normal emissivity measurements are carried out, evaluating the emissive properties of refractory firebricks before and after applying a high emissivity coating at elevated temperatures. The emissive properties are enhanced significantly after applying a high emissivity coating. Pilot unit steam cracking experiments show a 5% reduction in fuel gas firing rate after applying a high emissivity coating on the refractory of the cracking cells. A parametric study, showing the effect of reactor coil and furnace wall emissive properties on the radiative heat transfer inside a tube-in-box geometry, confirms that a non-gray gas model is required to accurately model the behavior of high emissivity coatings. Even though a gray gas model suffices to capture the heat sink behavior of a reactor coil, a non-gray gas model that is able to account for the absorption and re-emission in specific bands is necessary to accurately model the benefits of applying a high emissivity coating on the furnace wall.

• Klíčová slova
• energy efficiency, high emissivity coating, radiative heat transfer, spectral normal emissivity,
• Publikační typ
• časopisecké články MeSH

During the millions of years of evolution, photosynthetic organisms have adapted to almost all terrestrial and aquatic habitats, although some environments are obviously more suitable for photosynthesis than others. Photosynthetic organisms living in low-light conditions require on the one hand a large light-harvesting apparatus to absorb as many photons as possible. On the other hand, the excitation trapping time scales with the size of the light-harvesting system, and the longer the distance over which the formed excitations have to be transferred, the larger the probability to lose excitations. Therefore a compromise between photon capture efficiency and excitation trapping efficiency needs to be found. Here we report results on the whole cells of the green sulfur bacterium Chlorobaculum tepidum. Its efficiency of excitation energy transfer and charge separation enables the organism to live in environments with very low illumination. Using fluorescence measurements with picosecond resolution, we estimate that despite a rather large size and complex composition of its light-harvesting apparatus, the quantum efficiency of its photochemistry is around ~87% at 20 °C, ~83% at 45 °C, and about ~81% at 77 K when part of the excitation energy is trapped by low-energy bacteriochlorophyll a molecules. The data are evaluated using target analysis, which provides further insight into the functional organization of the low-light adapted photosynthetic apparatus.

• MeSH
• bakteriochlorofyl A fyziologie   MeSH
• Chlorobi fyziologie   MeSH
• fluorescence MeSH
• fluorometrie metody   MeSH
• fotochemie * MeSH
• fotosyntéza * MeSH
• fyziologická adaptace MeSH
• přenos energie fyziologie   MeSH
• světlosběrné proteinové komplexy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriochlorofyl A MeSH
• světlosběrné proteinové komplexy MeSH

This paper assesses the multiplexing efficiency of environmental taxes in ensuring environmental, energy, and economic security which is an integral part of sustainability in six European countries that are leaders in the Environmental Performance Index. This study aims to confirm the hypothesis that environmental taxes and payments could simultaneously affect changes in important environmental, energy, and economic security as well as sustainability parameters. Not all the previously selected taxes, which affect the parameters of all three areas of environmental, energy, and economic sustainability and security can ensure their simultaneous growth. Calculations made for the period 1994-2019 showed that in the system of environmental taxation of Denmark, five environmental taxes and fees provide an increase in the integrated level of environmental, economic, and energy security and sustainability; in Belgium, two environmental taxes are characterized by multiplex efficiency; in France, seven environmental taxes and payments; in Austria, four; in Finland, one; and in the UK, four. The paper's findings could create the basis for improving environmental taxation systems in the countries to increase comprehensive national security growth and ensure sustainable development path of the countries.

• Klíčová slova
• Environmental tax, Environmental, energy, and economic security, Multiplex effectiveness,
• MeSH
• daně * MeSH
• ekonomický rozvoj * MeSH
• trvale udržitelný rozvoj MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH
• Rakousko MeSH

One of the main aims of European Common Agricultural Policy (CAP) has been established on a considerable reduction of greenhouse gas (GHG) emissions without any decline in productivity by 2030. This introduces some challenges in the assessment of agricultural technical efficiency. In particular, we can formulate at least two problems that are worth to be addressed: (i) possibility of treating undesirable outputs and (ii) panel data analysis of agricultural technical efficiency enriched by eco-efficiency assessment. In this study, we applied a Window Slack-Based Measurement Data Envelopment Analysis (W-SBM-DEA) model in the presence of undesirable outputs to evaluate the performance of agriculture sector of EU-27 countries during the period from 2008 to 2017. The country-level cultivated agricultural area, labor, specific costs, overheads, and depreciation were considered as the model inputs, and the gross value of country-level crop and livestock products represented the desirable outputs. The agricultural total GHG emissions at the country-level were accounted for as the undesirable output in the model. Having compared the results of different models, the substantial difference in the performance of the EU countries was registered mainly due to incorporating undesirable outputs and window analysis when using SBM-DEA model. The results of eco-efficiency assessment indicated that the Netherlands, Belgium, Italy, and Malta are the most eco-efficient countries with a score higher than 0.90, while the lowest eco-efficiency scores were reported for Slovakia, Latvia, and Estonia. The highest average eco-efficiency scores of all EU members were registered in 2011 (0.82), 2012 (0.83), and 2017 (0.84). A comparison of eco-efficiency performance between the old and new EU members indicated that the greater scores were obtained by old EU members. The variability assessment results showed a low variability and subsequently a high stability in the European agricultural sector, particularly in the Netherlands, Italy, and Malta. Based on our findings, it was concluded that for assessing agricultural technical efficiency in European agriculture in the context of eco-efficiency, application of a W-DEA model with undesirable output for a specified period of time reduces the impacts of temporary changes and provides more realistic results when comparing to models without undesirable output. These more realistic assessments of technical efficiency could help policy-makers to make more precise decisions.

• Klíčová slova
• Agriculture, Eco-efficiency, European Union, Productivity, SBM, Undesirable output, Window-DEA,
• MeSH
• Evropská unie MeSH
• skleníkové plyny * MeSH
• výkonnost MeSH
• zemědělství MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Nizozemsko MeSH
• Názvy látek
• skleníkové plyny * MeSH

Different mechanistic models for potassium ion uptake are analyzed by an equilibrium-thermodynamic formalism in terms of their comparative efficiency in setting chemical potential differences of the potassium ion of different magnitudes across the plasma membrane of lower eukaryotic cells. The possible adaptive advantages for a multimode mechanism(s) operating in alternative modes depending on the physiological and/or environmental conditions of the cells are discussed.

• MeSH
• biologické modely MeSH
• buňky metabolismus   MeSH
• draslíkové kanály metabolismus   MeSH
• energetický metabolismus * MeSH
• eukaryotické buňky metabolismus   MeSH
• protonové ATPasy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• draslíkové kanály MeSH
• protonové ATPasy MeSH

The International Maritime Organization has set a goal to achieve a 50% reduction of total annual greenhouse gas emission related to the international shipping by 2050 compared to the 2008 baseline emissions. Malaysia government has taken an initiative to investigate the assessment (cost-effectiveness) of this International Maritime Organization's short-term measure on Malaysian-registered domestic ships although this measure is only for international merchant ship. To achieve this, this paper collected the ship's data from the shipowners from 25 sample ships. Engine power limitation is the most cost-effective option, but low power limits can lead to substantially increased sailing times. Based on cost-efficiency analysis, it creates for the purpose of compliance with the operational carbon intensity indicator. It found that even if it is possible to bring an asset back into service, it may not be possible to do so in a manner that generates a profit or complies with applicable regulations. In these situations, it may be more prudent to scrap the asset rather than run the risk of having it become a stranded asset. This is especially true for older tankers. Alternatives with lengthy payback periods are not desirable for the domestic tanker fleet that is already in operation.

• Klíčová slova
• Cost-effectiveness, Decarbonization, Malaysian-registered domestic ships, Shipping,
• MeSH
• lodě * MeSH
• skleníkové plyny * MeSH
• zachování přírodních zdrojů MeSH
• zachování zdrojů energie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• skleníkové plyny * MeSH