Cycle Efficiency Research Articles

Centrality of Phosphate Binding Modes on Metal Vanadate in Exploiting Low-Temperature NOX Reduction and Pyrosulfate Dissociation Pathways

PO43- guests anchored on metal vanadate hosts are as vital as SO32-/SO42- analogues in wide exploitation for expediting acidic/redox SCR cycles or ABS pyrolysis at low temperatures. This is due to their multiple roles as a provider of Brönsted acidic bonds (BA--H+) and as a dictator of the traits for labile/mobile oxygens (OL/OM) and oxygen vacancies (OV). However, the relationships of BA- (P5+-O2-)/BA--H+ (P5+-O2--H+)/OL/OV/OM feature for the host versus its mono-/bi-dentate PO43- binding mode (PO43-MONO/PO43-BI) has never been examined to-date. PO43- guests were thus grafted on MnV2O6 host at 300 °C and 400-500 °C to generate PO43-MONO-abundant P300 and PO43-BI-bountiful P400-P500, respectively. PO43-MONO species elevated OV hydrophobicity and OM mobility for P300, which were pivotal to enhance its H2O resistance and redox cycle efficiency over P400-P500, respectively. Conversely, PO43-BI species outperformed PO43-MONO counterparts in achieving higher OL nucleophilicity, which was central to reduce the SCR energy barriers and to promote acidic cycle efficiencies for P400-P500. Moreover, P500 had such hydrophobic BA- species that reveal the lowest energy barrier for pyrosulfate (S2O72- of dehydrated ABS) fragmentation among P300-500, thereby unveiling higher ABS resistance than P300-P400 and bi-dentate SO32-/SO42--ample MnV2O6 control with humid, poisonous gases being fed.

An optimization approach for improving steam production of heat recovery steam generator.

The heat recovery steam generator (HRSG) is a critical component of a combined cycle power plant, linking the gas turbine to the steam cycle. Optimizing the parameters affecting HRSG's steam outputs is critical for the design of combined cycle plants to maximize steam cycle efficiency. However, detailed optimization of the HRSG is a difficult task due to numerous parameters. Consequently, this paper aims to explore the impact of the parameters affecting the HRSG's ability to generate steam. In addition, response surface methodology and artificial neural network are used to build a mathematical relation between the steam production and the input parameters with the aim to determine the optimal values of the parameters to maximize steam production. The proposed models are effectively constructed and tested using real datasets. The findings revealed that the most parameters affecting steam production include high-pressure (HP) feed gas flow, HP feed gas pressure, and the interaction between low-pressure (LP) feed gas pressure, and HP feed gas flow. In addition, the results showed that the interaction between the input parameters and the quadratic terms have a significant impact. The results also indicated that the proposed models for both approaches predict the future of steam production with an accuracy of 99%. The results also showed that the proposed model selects and provides the optimal HRSG parameter values to maximize steam production within the relevant defined constraints.

Modern information technologies in thermal power calculations: Smath package and optimization of thermodynamic cycles of power plants

RELEVANCE. The relevance of this work lies in the creation of a certified software package (SEC), which is focused on solving problems of interest to the thermal power industry. One of the tasks chosen by the authors is devoted to improving the efficiency of the well-known gas turbine cycle by modernizing the thermal power circuit, which refers to a gas turbine plant (GTP). It should be noted that for CHP and GTP, the problem of increasing/improving energy criteria (Z1 - electrical efficiency, Z2-thermal efficiency, etc.) is a priority. The article considers in detail a number of objects, among them there are: a) the domestic mathematical package (MP) SMath, b) the package of functions (PF) WaterSteamPro, c) websites, d) the computer environment (CS) Linux. When creating the SEC, the authors solved issues those are relevant, firstly, for generating plants, including thermal power plants and combined cycle gas plants (CCGP); secondly, the authors considered the problems that play an important role in the modernization of the GTP, which includes a recovery boiler. Purposes. The authors consider several goals. The first is related to the development of method I, which should ensure the optimization of criteria characterizing the PGU-1 power plant under study. This technique is based, in particular, on Information Technology (IT); it uses a number of open interactive (OS) algorithms. These algorithms allow the researcher to conduct thermal energy (TE) calculations aimed at determining energy criteria, Z = (Z1, Z2, ...). Based on method I, the PROBLEM (A) is solved, which is related to the search for optimal parameters, Yopt= (Y1, Y2, ...), characterizing the thermodynamic cycle of PGU-1, here Y1 is the temperature at the inlet to the compressor, Y2 is the pressure at the inlet to the gas turbine. The second goal is related to the creation of a "Multifactor technology for the formation of OS algorithms." This technology makes it possible for a researcher who performs TE calculations to attract such tools that correspond to the world level of IT (SMath MP, Linux MP, Mathcad Calculation Server tool, etc.). In accordance with the second goal, a number of TASKS are being solved; among them is a task aimed at the SEC complex, as well as the task of creating an OS algorithm for TE calculations that are focused on PSU and MP Linux. Results. The article describes, firstly, the SEC complex. Secondly, the TE calculations were performed in accordance with the tasks set. So, in task (A), the PGU-1 is analyzed, which contains a number of blocks (a steam turbine; a part aimed at the internal heating of a vocational school, a heat recovery boiler, etc.). As a result, numerical data and graphical illustrations were obtained, including an assessment of the criterion Z2= 48.68% for the vocational training unit under Yopt conditions and a thermal power scheme for PGU-1 was selected. Conclusions. Currently, for well-known reasons, domestic researchers are switching from foreign software to domestic developments. An analysis of the results obtained in these TE calculations allows us to conclude: SMath MP and the SEC complex have enabled researchers to successfully abandon software that relies on Mathcad MP, Maple MP, Mathematica MP and MATLAB MP.

Linoleic acid alleviates aluminum toxicity by modulating fatty acid composition and redox homeostasis in wheat (Triticum aestivum) seedlings.

Lipids, as key components of biological membranes, play vital roles in sensing and initiating plant responses to various abiotic stresses. Here, the alteration of membrane fatty acids in wheat roots under Al stress was investigated using two genotypes differing in Al tolerance, and the role of linoleic acid in Al tolerance was comprehensively explored. Significant differences in the fatty acid profiles were observed, with increased linoleic acid accumulation in the Al-tolerant genotype. Supplementation with linoleic acid enhanced fatty acid synthesis, reduced membrane lipid saturation, improved membrane fluidity, and alleviated root growth inhibition. Wheat seedlings treated with linoleic acid exhibited a reduction in lipid peroxidation, as evidenced by decreased levels of malondialdehyde and lipid hydroperoxides. Furthermore, the application of linoleic acid increased the total contents and reduced forms of ascorbic acid (AsA) and glutathione (GSH), thereby restoring the cellular redox balance in wheat roots under Al stress. The elevated levels of AsA and GSH maintained by linoleic acid, can be attributed to the high efficiency of the AsA-GSH cycle, as linoleic acid enhanced the activities of the antioxidant enzymes involved. These results suggest that linoleic acid enhances wheat Al tolerance by maintaining both fatty acid synthesis and the levels of unsaturated fatty acids, as well as protecting membrane lipids from peroxidation by reactive oxygen species through the regulation of the AsA-GSH cycle.

Efficiency of geothermal Organic Rankine Cycle and methodologies for enhancement

Efficiency of geothermal Organic Rankine Cycle and methodologies for enhancement

α-tocopherol deficiency in follicular ovarian cyst (FOCs) follicular fluid (FF) elevates oxidative stress and impairs oocyte maturation.

Follicular ovarian cysts (FOCs) are prevalent reproductive disorders in both humans and animals, especially in livestock, where they cause economic losses by reducing fertility and productivity. FOCs are marked by a dominant follicle that fails to ovulate, disrupting the estrous cycle and reproductive efficiency. Previous studies indicate that the follicular fluid (FF) in cystic ovaries shows oxidative imbalance, affecting oocyte quality by altering glutathione peroxidase (GPX1) and selenium pathways. However, the metabolic profile of FF in cystic ovaries needs further exploration. This study examined oxidative stress and metabolic changes in FOC pathogenesis. Using untargeted metabolomics of goat FF, we found significant differences in 12,741 metabolites between cystic and control FF. Cystic FF had reduced levels of α-tocopherol and 8'-apocaroten-8'-ol, key for oxidative stress management, and increased levels of mycotoxins (e.g., Deoxynivalenol-3-glucoside) and long-chain fatty acids. Adding 200 μM α-tocopherol to FOC FF oocyte cultures doubled oocyte maturation rates and decreased reactive oxygen species (ROS). Metabolomic analysis linked low α-tocopherol to high lipid peroxyl radicals and low glutathione oxidation, emphasizing oxidative stress regulation's importance in the follicular microenvironment. Our findings suggest that α-tocopherol may serve as a biomarker and therapeutic agent to enhance oocyte maturation in FOCs.

The Impact of Building Material Modeling on Enhancing Building Sustainability (Carbon Emissions): A Case Study of a Residential Building in Basilia

This study addresses the impact of modeling building materials on improving building sustainability by analyzing a case study of a residential building in the Baselia area of Damascus, which has experienced the removal of orchards, leading to negative environmental impacts. The research focuses on evaluating the carbon footprint of the building materials used in the structure and cladding, utilizing Autodesk Forma to analyze life cycle and energy efficiency. The study includes an analysis of the impact of five different building materials on carbon emissions during the stages of production, transportation, installation, use, and disposal. Results show that composite steel has the highest carbon emissions compared to other materials, while wood materials, such as timber frame and mass timber, have the lowest emissions. For internal cladding, the differences between materials were relatively minor. The study recommends selecting building materials with lower environmental impact and enhancing energy efficiency, which contributes to reducing carbon emissions in the construction sector and supports achieving sustainability goals.

Investigation of Combine Cycle Power Plants with Low-Grade Heat Utilization Working Methane-Hydrogen Mixtures

The Russian energy sector remains heavily reliant on thermal power plants, with gas generation accounting for approximately 66% of the installed capacity. However, the industry faces challenges such as depletion of reserves, rising prices for hydrocarbons, and increasing concentrations of carbon dioxide in the atmosphere. This study focuses on developing new scientific and technical solutions to increase the efficiency and environmental safety of combined cycle power units. The research involves structural and parametric optimization of trinary cycle power plants operating on a methane-hydrogen mixture, as well as the development and optimization of turbine and heat exchange equipment for low-temperature power plants. The results show that the transition to trinary CCGT (Combine Cycle Gas Turbine) units with deep utilization and the use of hydrogen fuel can significantly reduce specific CO2 emissions and increase energy efficiency up to 0.21% with also increases in capacity of turbine of approximately 17 MW. The aim of this research is to calculate the efficiency, cost effectiveness and environmental-friendly solution for power generation using mixture of hydrogen- methane as fuel in combine cycle power plant that includes ORC. Additionally, the efficiency of the organic Rankine Cycle (ORC) benefits from the increased moisture, with capacity improvements of 1-2 MW observed when the hydrogen proportion rises from 25% to 50%. Moreover, the potential for zero emissions, coupled with significant increases in power output and efficiency, underscores hydrogen's role as a pivotal component in the future of energy production.

Climatic Influences on the Environmental Performances of Residential Buildings: A Comparative Case Study in Turkey

This study evaluates the environmental performance of residential projects in Bolu and Mardin, Turkey, by assessing the impact of climatic and architectural context on material selection, construction techniques, and environmental outcomes. Using BIM-based LCA tools, the analysis compares Bolu’s humid climate with Mardin’s hot and dry conditions across multiple environmental metrics. In the Product (A1–A3) phase, Bolu has higher CO2 emissions, accounting for 79–85% of the total environmental impact, compared to 77–82% in Mardin. However, energy consumption is higher in Mardin during the Product phase. In the Construction (A4) and End of Life (C2–C4) phases, Bolu has a higher energy consumption and environmental impact than Mardin. In terms of waste generation, the End of Life phases (C2–C4) are identified as significant contributors in both case studies. The material analysis shows that concrete, finishing materials (e.g., paint and plaster) and stone wall materials have the highest environmental impacts in both cases. This study aims to provide a detailed examination of how environmental impacts differ due to material use in two different climatic regions. BIM-based LCA methods were used to investigate the influence of regional and climatic differences on environmental performance. The impacts of material components across all life cycle stages were analyzed, and recommendations for their optimization were provided. Future research could focus on the integration of innovative materials and technologies to improve life cycle efficiency. In addition, incorporating data from different geographic regions could broaden the scope of the analysis and contribute significantly to sustainable building practices. Such approaches provide critical opportunities to develop specific strategies for reducing environmental impacts.

Low-grade heat utilization for combined cycle power plants using organic rankine cycle

This paper presents a comprehensive thermodynamic analysis of trinary power plants, focusing on the efficiency of Organic Rankine Cycle (ORC) configurations and regenerative heating methods. Despite advancements in nuclear and renewable energy, fossil fuels still dominate electricity generation, necessitating improved efficiency in existing power plants. The study reveals that low-pressure mixing-type heaters provide higher efficiency compared to surface heaters, with net efficiencies of 0.099%, 0.227%, and 0.425% at deaerator pressures of 0.12, 0.3, and 0.7 MPa, respectively. The analysis highlights the impact of feedwater temperature on the thermal efficiency of steam turbine units (STUs), noting that while optimal feedwater temperatures enhance efficiency, they can reduce STU capacity. The study identifies configurations for regenerative heating that optimize exhaust gas temperatures, facilitating additional electricity production through a low-boiling working fluid in the ORC. The findings indicate that R245fa refrigerant is optimal for ORC without recuperative heater, achieving maximum net power at a feedwater temperature of 115°C. For ORC with a recuperative heater, R236ea is preferred for temperatures between 115°C and 154.5°C, while R245fa is optimal for higher temperatures. The results also demonstrate that trinary power plants with recuperators achieve greater efficiency and net capacity compared to double-circuit systems, with notable improvements in thermal efficiency attributed to effective regeneration schemes. This research underscores the potential for optimizing existing domestic power units to enhance their efficiency and performance without significant financial or technical burden, thereby contributing to more sustainable energy generation.

Ecological restoration orientated application and modification of constructed wetland substrates.

Constructed wetlands (CWs) have gained recognition as an environmentally friendly and cost-efficient option for treating municipal, industrial, and agricultural wastewater. They treat wastewater by harnessing the combined action of physical, chemical, and biological processes within substrates, plants, and microorganisms, with substrates exerting the greatest influence on the life cycle and purification efficiency of the system. This review provides an in-depth discussion on the development and performance of various substrate types used in CWs, including natural materials, ore-based materials, biomass materials, waste materials, and modified and novel materials. Key substrate modification techniques are summarized in detail, such as acid-base treatment, metal doping, compound modification, and heat treatment, which enhance structural and functional properties to improve pollutant removal. The paper also systematically explores the mechanisms of introducing methods like inorganic electronic enhancement and describes their applications in improving pollutant removal in CW systems. This review provides a holistic evaluation of substrate classification and optimization strategies and a prospective discussion of their challenges and opportunities in practical applications. It contributes to the creation of more efficient and sustainable materials for CW systems and provides theoretical support for selecting and optimizing substrates, thereby driving progress in wastewater treatment technology.

Environmental and economic aspects of improving the energy efficiency of the vaccine production life cycle

The work is devoted to the analysis of the impact of energy efficiency improvements on the environmental and economic aspects of the vaccine production life cycle. In the context of the growing need for global vaccination and taking into account significant losses due to violations of the cold chain, the study focuses on reducing energy consumption and optimizing resource use. The analysis of costs, greenhouse gas emissions, and the impact on the cost of vaccines will determine the economic and environmental benefits of implementing energy-efficient technologies, contributing to sustainable development and increasing the availability of vaccination.

Assessment of heat storage integration for water vapour compression heat pumps: thermodynamic and techno-economic perspectives

ABSTRACT The integrated system, consisting of a two-stage high-temperature heat pump (HTHP) and thermal energy storage (TES), has been proposed as an effective solution to reduce CO2 emissions in industrial processes effectively. The water vapour HTHP, which can supply heat at 200°C, demonstrated a coefficient of performance (COP) between 4.4 and 7.5. Two different TES systems were introduced: concrete sensible heat storage (SHS) and strontium bromide/water (SrBr2/H2O) thermochemical energy storage (TCES). While the concrete SHS is limited to temperature below 200°C, the SrBr2/H2O TCES can deliver heat between 196°C and 228°C with higher cycle efficiency. The integrated system of HTHP and SrBr2/H2O TCES achieved a net present value (NPV) of €464,559 and €182,374 over a 20-years lifespan, with internal rates of return (IRR) ranging from 15.8% to 23.6%. This HTHP and TCES system has sufficient potential to replace fossil-fuel industrial boilers, leading to significant reduction in CO2 emissions in industrial processes.

Gasification of Chlorella vulgaris for Syngas Production and Energy Generation Through Gas Turbine

The increasing need for sustainable energy sources has driven research toward innovative solutions, including biomass gasification for syngas production, with applications in the chemical industry and energy generation. This study explores the application of Chlorella vulgaris in the gasification process to produce syngas intended for gas turbine operation. Using Aspen Plus V11 (academic version) simulations, the study evaluates optimal process conditions and syngas yields, focusing on operational parameters such as the S/B ratio and gasifier temperature. Results show that a higher S/B ratio increases H2 and CO2 concentrations while reducing CO and CH4, with final syngas composition in dry conditions reaching 0.42 CO, 0.52 H2, and 0.036 H2O. Contaminants like H2S and HCl were effectively reduced below critical thresholds, with H2S levels under 20 ppm and HCl under 1 ppm to meet GT requirements. The system achieved a cold gas efficiency of 55% and an overall turbine cycle efficiency of 25%, with CO2 emissions of 0.198 kg per kWh produced. In conclusion, the gasification of C. vulgaris offers a promising and sustainable solution for syngas production and energy generation, with reduced environmental impacts. However, economic feasibility and certain technical challenges will require further advancements to fully realize this technology’s potential.

Maximum thermal efficiencies of supercritical CO2 power cycle at various power capacities

Maximum thermal efficiencies of supercritical CO2 power cycle at various power capacities

Analysis of a Coupled Calcium Oxide-Potassium Carbonate Salt Hydrate based Thermochemical Energy Storage System

A coupled thermochemical energy storage (TCES) system consisting of calcium oxide (for high temperature storage) and potassium carbonate salt hydrate (for medium temperature storage) is analyzed for long-term high temperature heat storage. The coupled TCES system is expected to have smaller volume requirement as evaporator and condenser of the conventional TCES system are replaced by a second reactor. The rate expressions for hydration-dehydration reactions of both storage materials are modified to calculate the reaction completion times, which provide the rate limiting process. A thermodynamic analysis is carried out for the operating cycle of the coupled TCES system to study the impact of operating parameters on the system performance. It is observed that the charging temperature of the individual storage material has significant impact on the performance of the coupled TCES system. The analysis reveals that the coupled TCES system with optimized parameters operating in a cold ambient at 10 °C, achieves a cycle efficiency of 58.6 %, exergy efficiency of 49.1 %, specific heating power of 127.8 W kg-1 and volumetric energy storage density of 269.0 kWh m-3.

Recent Advances on Electrolyte Additives Regulating the Electrode/electrolyte Interface to Stabilize the Zinc Anode

Energy and environment are the two most serious problems in todays social development. With the depletion of fossil resources such as coal and oil and the deterioration of the environment, the development of renewable energy has become a new trend. As an emerging energy storage technology, aqueous zinc-ion batteries (AZIBs) have attracted widespread attention due to their low cost, high safety, good environmental sustainability, and high energy density. However, problems such as dendrite growth in zinc anode, electrolyte decomposition and cathode dissolution limit its commercial application. In order to overcome these challenges, the research of electrolyte additives has become a hot field. Electrolyte additives can improve the cycle stability and efficiency of aqueous zinc-ion batteries by regulating the electrode/electrolyte interface, stabilizing the zinc anode, and improving the overall performance of the battery.

Frequency-dependent ferroelectric heat cycles in polymer blends: Enhancements in electrocaloric performance of P(VDF-TrFE) and P(VDF-TrFE-CTFE)

Copolymer (P(VDF-TrFE-CTFE)) and terpolymer (P(VDF-TrFE)) have been widely investigated for their promising electrocaloric effect (ECE), whereas, their mixture of ECE has not been investigated. In this work, P(VDF-TrFE was mixed with a variety of concentrations of P(VDF-TrFE-CTFE) and its ECE effect was investigated in detail. Results indicated that after mixing of the copolymer, an additional change of adiabatic temperature (T + Tad) could be obtained. Moreover, the energy density (ND) is drastically enhanced when the copolymer concentration increases up to 3 % due to antiferroelectric behavior of polymer blends (i.e. Copolymer content = 30 wt%). In addition, we observed that we can tune the working of frequency dependent ferroelectric heat cycle instead of pyroelectric heat cycle by changing the operational frequency in antiferroelectric range and the rejection of output heat is increased by decreasing the operational frequency (from 10−2Hz to 102 Hz). And we propose to use ΔT Vs E loop as the criteria to explain the ferroelectric heat cycle. Using this novel technique, we could successfully compare the efficiency of heat cycles. Three times higher efficiency of ΔT-E loop at low frequency (10−2 Hz) was achieved due to the blend's antiferroelectric behavior.

A semi-empirical relation based on temperature difference and filling ratio in a closed loop pulsating heat pipe: A numerical study.

A closed-loop pulsating heat pipe (CLPHP) is an attractive passive cooling system for electronic components. The design of CLPHP is challenging due to the complex nature of thermo-hydrodynamic coupling. This study investigates the heat transfer efficiency of a CLPHP using water as the working fluid. The heat transfer rate is evaluated for a volume fraction of 0.3-0.7 and an evaporator temperature of 323-373 K. From the computed results, a regression analysis is performed to generate a semi-empirical equation. The empirical relation for heat transfer rate (Q) as a function of the temperature difference and filling ratio was found to match the CFD results. Similarly, a semi-empirical equation for heat flux (q) as a function of non-dimensionless numbers is presented to calculate the heat transfer rate (Q) for various filling ratios, and found to match CFD results. A force plot measuring the net force acting on the slugs is presented for various filling ratios and evaporator temperatures. The net force plot will help optimize the design of the CLPHP and improve its efficiency. When comparing slug formation pulsatile cycle and thermal efficiency, 0.5 volume fraction was found to be optimum. For this filling ratio (0.5) heat transfer rate is enhanced from 40% to 86% when the evaporator temperature is increased by 15%.

Performance evaluation of supercritical CO2 Brayton cycle with two-stage compression and intercooling

Due to its small structures and high energy efficiency, the Brayton cycle using supercritical carbon dioxide (sCO2) can be implemented in various energy industries. The simulation model for a sCO2 recompression Brayton (RB) system with a two-stage compression and intercooling process (TCIP) is developed. At the design working conditions, there are minimum and optimum split ratios for the sCO2 RB with TCIP cycle. The sCO2 RB with TCIP cycle has a broader range of split ratios compared to the RB cycle. The sCO2 RB with TCIP cycle can achieve a minimum split ratio of 0.315, compared to 0.36 for the sCO2 RB cycle. The maximum efficiency of the sCO2 RB with TCIP cycle is 50.95 %, which surpasses the efficiency of the sCO2 RB cycle by 3.14 %. There exists an optimal value for the first-stage pressure ratio because the maximum efficiency of the sCO2 RB with the TCIP system tends to increase and then decrease with the increase in the first-stage pressure ratio. The pressure ratio of 1.1 for the first-stage compressor, corresponding to an interstage pressure of 8.25 MPa, maximizes the efficiency of the sCO2 RB with the TCIP cycle. The results can be used to further explore the applicability of sCO2 RB with TCIP.