This article examines in detail the technological processes, operating parameters and technical characteristics of pump-compressor stations used in the "Garadagh" and "Galmaz" underground gas storage facilities of Azerbaijan. Underground gas storage facilities are vital infrastructure facilities for seasonal and strategic storage of natural gas. The efficient operation of these storage facilities plays an important role in ensuring the country's energy security. The article analyzes the technical problems encountered in the operation of pump-compressor stations, the operating modes of equipment, the impact of pressure changes on the system and ways to increase energy efficiency. Also, technological solutions that ensure optimal operation of pump and compressor units in the processes of pumping and extracting gas from storage facilities are considered. The results of the study show that the application of modern automation systems, systematic monitoring of the technical condition of equipment and planning of preventive maintenance work significantly increase the reliability of pump-compressor stations. The article is intended for specialists and researchers working in the field of operation of underground gas storage facilities. The purpose of the article is to analyze in detail the technological processes, operational parameters, technical problems, and ways to increase energy efficiency of the pump-compressor stations used in the "Garadagh" and "Galmaz" underground gas storage facilities. Keywords: underground gas storage, pump-compressor station, compressor units, pressure regime, energy efficiency, technical operation, automation systems, Garadagh, Galmaz.

This article investigates the impact of ambient air temperature on the fuel gas consumption of a gas pumping unit using the GPA-16R «Ufa» as a case study, which is actively operated by Gazprom Transgaz Ufa, LLC. The analysis is based on operational data from the unit during the period from 12.04.2024 to 03.05.2024. The results show that with stable power consumption by the centrifugal compressor of the gas pumping unit, an increase in the inlet air temperature to the low-pressure compressor leads to an increase in fuel gas consumption. It has been established that a decrease in ambient air temperature contributes to a reduction in natural gas consumption, which is confirmed by actual operational data. This study emphasizes the importance of exploring methods to reduce fuel gas consumption, particularly through cooling the air entering the gas-air duct of the gas pumping unit. In conditions where natural gas consumption accounts for up to 91 % of the total consumption of fuel and energy resources in Gazprom, PJSC, optimizing fuel consumption becomes especially relevant.During the analysis, groups of parameters reflecting the dependence of fuel gas con-sumption on the temperature at the compressor inlet at various gas pumping unit power levels were identified. The results indicate a linear relationship between these variables, suggesting the potential for increased energy efficiency of the units at lower air temperatures.Thus, the findings of the study highlight the necessity for developing technical solutions aimed at cooling the air entering the gas pumping unit, which could lead to significant fuel savings and improved overall efficiency of the gas transportation system. Future research plans include expanding the study to analyze the impact of other factors, such as humidity and pressure, on fuel gas consumption, allowing for a more comprehensive assessment of the potential for enhancing the energy efficiency of gas pumping units. Additionally, the implementation of innovative energy-saving technologies, such as turboexpander installations, heat recovery systems, and vortex tubes, is also proposed, which could further contribute to reducing fuel costs and improving the environmental performance of the gas transportation system.

Against the backdrop of intensifying global climate change and frequent climate-related disasters, carbon neutrality has become a common goal worldwide. The European Green Deal, initiated by the European Union (EU), sets forth a strategic objective to achieve carbon neutrality by 2050. It seeks to change the energy system through three key strategies: promoting renewable energy, increasing energy efficiency, and ramping up investment in green technologies. However, the energy crisis sparked by the Russia-Ukraine conflict, along with slow progress in renewable energy adoption, has highlighted the institutional obstacles and path-dependent issues within Europe's energy transition. The differing energy policies of member states, technical challenges, and political dependencies have all hindered the EU's progress toward its carbon neutrality goals. Thus, identifying effective approaches to break through these constraints has become the linchpin for advancing the green transition. Based on a review of policy documents issued by the EU and its member states, along with relevant academic literature, this paper analyzes the institutional changes and path-dependent issues encountered during the implementation of the European Green Deal, drawing on EU energy statistics. The results reveal that legal frameworks, capital allocation mechanisms, and social mobilization are the key drivers of the transition, while political constraints and technical bottlenecks are the main obstacles to progress. To overcome path dependence, the EU must strengthen customized policy design, optimize funding support mechanisms, and promote cross-border technological collaboration. By doing so, the EU can strike a balance between maintaining policy coherence at the bloc level and enhancing geographical flexibility, thereby offering valuable insights for the global endeavor to attain carbon neutrality.

We currently live in a world in which dynamics are increasing ever more rapidly and changes are occurring at tremendous speed. This affects not only political and economic systems as well as social networks, but also our climate. Never before in human history has the temperature risen as quickly and dramatically as it has in recent years. There is scientific consensus that is due to the immense quantities of greenhouse gases that we continuously emit. In order to limit this anthropogenic rise in temperature, we must therefore decarbonize our energy supply as quickly as possible. On this point, there is broad agreement among most established political parties as well as a wide societal consensus. Key to the decarbonization of our energy system are measures to increase energy efficiency and the transition from fossil fuels to renewable energy sources. Compared to other sectors, heat supply is currently lagging behind. Nature provides us with an extensive portfolio of options, ranging from solar radiation and wind to biomass, geothermal energy, and ambient heat. For this reason, we decided to expand the former “Solarthermie” symposium to address all options for a climate-neutral heat supply for buildings, districts and heating networks, as well as industrial processes. A wide range of expert contributions at the “Symposium Zukunft Wärme” presents new technological developments, application examples, and operational experiences from the fields of solar thermal energy, heat pumps, and biomass, combined with innovative technologies for the efficient use, storage, and distribution of heat.In addition, a broad spectrum of different energy concepts for individual buildings quaarters, local and district heating systems, and industrial processes will be presented – among other things, taking into account aspects of sector coupling through heat pumps, power-to-heat, as well as combined heat and power plants and fuel cells. In addition to technology, legal and political framework conditions, as well as market mechanisms and economic viability, are of decisive importance. These aspects will therefore also be addressed in the presentations and, of course, in the discussions at the symposium “Zukunft Wärme”. Not only our world developing at an ever-faster pace, but the field of renewable energy and heat supply is also characterized by strong dynamics – both in research and development and in practical implementation. The Scientific Advisory Board, the Conexio-PSE team, and we as the technical chairs of this year’s symposium are therefore very much looking forward to spending several interesting, exciting, and forward-looking days with you at Kloster Banz, where we can exchange views on current and future developments together.

Glycolytic ATP production declines with age, contributing to common aging phenotypes such as reduced cell division and impaired DNA & mitochondria repair. Notably, immortal cells exhibit a metabolic profile characterized by sustained, highly active glycolytic ATP production. A key unresolved question is the underlying mechanism driving the gradual decline in glycolytic ATP production during natural aging. We have found that this can be explained by the concept that a decline in glycolytic ATP production was crucial for survival of species, and only those species with an optimal rate of reduction in glycolytic ATP production over time were selected and persisted through generational changes. Sexual reproduction generates new combination of gene pairs with abundant DNA mutations during meiosis, which provides significant advantages in adapting to environmental changes and competence over other species. However, the population of species is limited because of finite food supply in the natural world. The shift from glycolysis to aerobic metabolism increases energy efficiency and the increased energy efficiency in parent generation benefits the species by enhancing survival of parent generation at starvation conditions and limited food allocation to the offspring generation. This conceptual framework can explain the finite lifespans of organisms, significant variations in lifespan across species, cellular immortality of cancer cells, and the exceptionally long life of the naked mole rat (Heterocephalus glaber). Although questions remain, this concept offers new insights into the biology of aging and potential strategies for rejuvenation therapies for humans.

Optimizing the mechanical response of structures with triple periodic minimal surfaces (TPMS) is key to their use in lightweight applications focused on energy absorption. This study evaluated the influence of cell geometry and uneven material distribution on the bending behavior of Primitive, Gyroid, and Diamond structures. Nylon 12 CF samples were produced using an additive method (FDM) with volume fractions of 35%, 40%, 45%, and 55%. The mechanical response was quantified using a three-point bending test according to ISO 178, from which the maximum force (Fmax), flexural strength (σf), absorbed energy (Eabs), and ductility index (µd) were determined. The Primitive structure achieved the highest strength at a volume fraction of 45% (σf = 28.35 MPa; Fmax = 756 N). The Primitive structure also demonstrated the highest toughness with a ductility index of up to µd = 8.62 at 55%. The study identified a significant deformation phenomenon in the Gyroid structure, where the sample with a volume fraction of 45% showed higher absorbed energy (34.58 J) than the sample with a higher fraction of 55% (26.81 J). This finding suggests that targeted material inhomogeneity (gradient) can, under specific conditions, lead to stabilization of the deformation mechanism through progressive collapse, thereby increasing energy efficiency. The Primitive structure proved to be the most resistant to uneven material distribution and, with a volume fraction of 45-55%, offers an optimal compromise between high strength and toughness, making it most suitable for the design of gradient structures subjected to bending loads.

In tropical areas, brick and wood are commonly utilised for wall construction. However, building occupants may experience temperature discomfort if inappropriate materials are used. To identify the ideal most comfortable temperature range and to increase energy efficiency, a field study was conducted in Majene City, Indonesia (tropical climate). Wooden-walled and brick-walled classrooms were used to measure environmental parameters, and questionnaires were distributed to assess students' thermal comfort. The neutral temperature of actual voting, obtained using Griffith's method and regression analysis, was compared with the result from the PMV/PPD and adaptive methods. The results showed that whereas classrooms with wooden walls had higher air temperatures, from 27.64 °C to 33.19 °C from morning to midday, classrooms with brick walls had air temperatures approximately between 27.52 °C and 30.67 °C from morning to midday. In addition, student responses indicate that brick-walled classrooms are more comfortable and have better thermal performance than wooden-walled classrooms. Griffith's method and regression analysis showed that the neutral temperatures of brick-walled classrooms (28.50 °C and 29.57 °C, respectively) were lower than those of wooden-walled classrooms (28.93 °C and 29.99 °C, respectively).

Ecuador, a country highly dependent on its oil industry, faces the need to import petroleum derivatives due to the lack of a developed petrochemical sector. This study comparatively assesses the technical, economic, and environmental feasibility of three routes for ethylene production, focusing on more sustainable and environmentally friendly processes. The first, the traditional linear process based on thermal cracking of naphtha, is noted for its technological maturity and lower initial costs, but operates under the "extract, produce, dispose" sequence, leading to a high environmental impact due to the substantial energy required and significant greenhouse gas emissions. In contrast, the two proposed circular routes utilize potato agricultural waste as biomass for bio-ethylene production: (a) fermentation to obtain bioethanol followed by catalytic dehydration and (b) electrocatalysis of methane derived from residual biomass. The study's results indicate that while these routes face technical and economic challenges, such as low yields, additional equipment for raw material processing, and higher initial costs, they offer environmental benefits aligned with green chemistry principles, including carbon emission reduction, use of renewable raw materials, and increased energy efficiency. Of the two circular processes analyzed, fermentation is considered the more applicable option due to biomass availability and process maturity in the local industry, despite having a cost 2.6 times higher than the linear process. While naphtha-based ethylene production remains the most viable in economic and technological terms, the development of a sustainable bio-ethylene industry still faces challenges in scalability, yields, and high initial costs but would allow the valorization of agricultural waste, diversifying the country's production matrix and positioning Ecuador as a leader in green innovation in Latin America.

Adjustment of heating curve in space heating system to real energy needs as easily applicable and effective measure to increase energy efficiency in existing buildings

The advancement of additive manufacturing has enabled the development of highly energy saving and compact heat exchangers with complex geometries, such as gyroid structures, which exhibit superior thermal-fluid performance. This study proposes a computational fluid dynamics (CFD) analysis of a gyroid-based heat exchanger designed for cooling applications using R290 refrigerant. The gyroid structure, characterized by high surface area density and low friction factor, was evaluated for its heat transfer efficiency and pressure drop characteristics. Numerical simulations were executed to assess the impact of flow velocity, pressure distribution, and temperature gradients on the gyroid heat exchanger’s performance. The coefficient of performance (COP) which indicates of the efficiency of a thermal system without a heat exchanger is 3.22, when using a gyroid heat exchanger for the superheat and subcooling process increases it to 3.29. The results demonstrate that the gyroid heat exchanger enhances convective heat transfer while maintaining relatively low-pressure losses, leading to a 2.2% improvement in the system's COP compared to conventional cooling system design. The findings highlight the potential of gyroid heat exchangers as next-generation compact thermal management solutions, contributing to increased energy efficiency in the industrial cooling applications.

Storks’ migration route planning capabilities have long been a focus of attention as a natural phenomenon. This study aims to examine these capabilities and provide a new perspective to the logistics sector. Inspired by the migration behavior of storks, the study presents a new logistics optimization model. The model is designed based on stork migration route planning strategies by combining nature-inspired approaches. By simulating the natural behavior of storks, the model aims to achieve basic logistics goals such as energy saving, cost reduction and effective time management. The stork-inspired logistics model is expected to provide significant advantages in logistics operations. It has the potential to increase energy efficiency, reduce costs, and improve operational efficiency in route planning. In addition, the model takes into account other important factors such as environmental sustainability and social impact. Although further research is needed to evaluate the real-world applicability and effectiveness of this model in logistics operations, it is clear that this approach provides several potential benefits to the sector. Future studies should focus on adapting the model to large-scale enterprises.

This paper presents a novel context-aware multi-agent coordination framework for dynamic resource allocation in smart EV charging ecosystems using distributed reinforcement learning. The system addresses the challenge of coordinating 250 autonomous charging agents while enabling real-time adaptation to changing environmental conditions. Our approach employs a coordinated Deep Q-Network (DQN) architecture where agents collaborate through consensus mechanisms and spatial-temporal contextual information. Experimental results demonstrate superior performance over centralized methods like DDPG, A3C, and PPO, achieving a 15% increase in energy efficiency, a 10% reduction in charging costs, and a 20% decrease in grid strain. The framework showed high reliability with a 92% context-adaptive coordination success rate under varying grid conditions. Comparative analysis across multiple batch sizes and training episodes revealed that this distributed DQN approach maintains 88% training stability and 85% sample efficiency, consistently outperforming context-agnostic and non-coordinated alternatives. The core contribution is a multi-stakeholder coordination protocol that balances five ecosystem perspectives: EV users (25%), grid operators (20%), station operators (20%), fleet operators (20%), and environmental factors (15%). By integrating variables such as traffic patterns, weather, and grid load fluctuations, the architecture effectively resolves competing interests, creating a scalable and collaborative solution for smart charging infrastructure.

Abstract Hybrid drying system uses both steam dryer and flue gas dryer to reduce fuel moisture content, which results in increasing energy efficiency of biomass power plant. It has been demonstrated previously that flash steam from blowdown heat recovery system may be used to operate hybrid drying system. Steam is supplied to steam dryer may be obtained from direct steam generating parabolic trough collectors. However, the intermittent nature of solar radiation means that steam dryer will have to operate inefficiently with variable steam supply. In this paper, it is proposed that direct steam generating parabolic trough collectors should be integrated with blowdown heat recovery system. The problem of the fluctuating solar radiation is solved by varying blowdown rate so that steam dryer receives steady steam supply. Blowdown rate is maximum when there is no solar energy, and blowdown rate is minimum when the maximum amount of steam is generated by parabolic trough collectors. The daily operation of the proposed system is divided into two modes depending on the availability of solar energy. It is demonstrated that the proposed system can reduce fuel consumption by 1.70 % annually compared with the reference system that supplies steam to steam dryer using only blowdown heat recovery system.

Continuous growth in prices for primary energy sources and environmental restrictions on pollutant emissions justify investments in industrial facilities to minimize specific energy consumption. In addition, oil-producing and refining enterprises were built in previous decades, when energy efficiency problems were not so urgent, so little attention was paid to the development and application of tools for improvement. In this regard, at present, the application and development of methods for increasing energy efficiency is certainly relevant, especially for oil processing and stabilization units (OPSUs) at fields, through which all oil produced in a country passes. Our goal is to achieve heat integration of OPSUs with a capacity of 4 million tons of processed raw materials per year. In this study, for the heat integration of the OPSU, pinch-analysis methods with the construction of grid diagrams are used for a retrofitting project for increasing the energy efficiency of the heat exchange network (HEN) of an OPSU. The heat and economic analysis of the synthesized HEN were performed using Pinch 2.02 software. This paper presents a retrofitting-based energy-efficiency project for the OPSU HEN. A method for evolving the synthesized HEN by breaking heat load paths is applied to increase the economic efficiency of the retrofit project. The stability of the OPSU operation in the optimal mode is shown with the observed change in the bank interest rate. The implementation of the synthesized HEN will reduce specific energy consumption by 77%, decreasing CO2 emissions released into the atmosphere by 30 thousand tons per year.

This study comprehensively analyses the energy, exergy, and environmental performance of alternative low GWP refrigerants used to replace R404A and R410A refrigerants, with high global warming potential (GWP), in vapor compression cooling systems. The refrigerants R454C, R452A, and R449A were analyzed as alternatives for R404A, while R454B, R452B, and R463A were analyzed for R410A. The analyses were executed at a stable condenser temperature of 40 °C and evaporator at temperatures varying between -25 °C and +5 °C. Energy performance was evaluated by cooling capacity and coefficient of performance (COP), while exergy analysis covered total exergy destruction and exergy efficiency. The environmental impact was determined using the Life Cycle Climate Performance (LCCP) method. The results show that R449A and R454C offer higher COP (with a maximum increase 6.87%) and exergy efficiency compared to R404A, whereas R454B and R452B increase energy efficiency and provide lower LCCP values compared to R410A. In contrast, R463A exhibits low energy and exergy performance and high emission values. Environmental analyses confirm that R449A and R454B significantly reduce greenhouse gas emissions. These findings suggest that R449A is a suitable environmentally friendly alternative to R404A, and R454B is a suitable environmentally friendly alternative to R410A, considering both thermodynamic efficiency and environmental impact.

Abstract Using panel data from 286 prefecture-level cities in China, this study constructs a city-level digital economy index and examines its impact on carbon emissions intensity and related mechanisms. Theoretically, the digital economy can reduce carbon emissions intensity by increasing energy efficiency. The empirical findings show that: First, the digital economy reduces carbon emission intensity, and this finding still holds after robustness tests such as the selection of city-to-port distance as an instrumental variable and the “Broadband China” pilots as a quasi-natural experiment. Second, the digital economy reduces carbon emissions intensity mainly by reducing the scale of energy consumption, optimizing the energy structure, and facilitating renewable energy deployment. Third, the carbon reduction effect of the digital economy is more pronounced in western and northeastern regions, second-tier and small cities, resource-based cities and peripheral cities. Finally, further analysis shows that the digital economy can mitigate environmental inequalities. On this basis, this paper puts forward proposals to vigorously develop the digital economy and promote the integration of digital and low-carbon development, in order to provide reference and reference to promote the high-quality development of the digital economy, thus empowering carbon emission reduction and achieving the equity of environmental welfare benefits.

Heat transfer efficiency in lubrication systems can be achieved by utilising nanolubricants by dispersing nanoparticle additives into pure lubricants to increase nanolubricant stability and thermal conductivity. This study aims to investigate the effect of silicon dioxide (SiO₂) nanoparticle dispersion in polyvinyl ether (PVE)-based lubricants on the stability and thermal conductivity characteristics of nanolubricants. SiO₂/PVE nanolubricant was prepared using a two-step method with a volume concentration of 0.007%. Stability evaluation was carried out through UV–Vis spectrophotometry testing over a period of 30 days. Thermal conductivity was measured using KD2-Pro at a temperature range of 30 ℃ to 80 ℃. The results of the study showed that SiO₂/PVE was declared stable after 144 hours with an absorbance of 80%. Thermal conductivity characteristics decreased with increasing temperature, and the nanolubricant increased compared to PVE lubricants. The maximum increase in thermal conductivity was 2.72% compared to the pure lubricant, and at a test temperature of 30 °C, SiO₂/PVE was compared to SiO₂/corn oil, SiO₂/paraffin oil, SiO₂/sunflower SiO₂/oil, and SiO₂/soybean oil; the results showed an increase in thermal conductivity of 66.69%, 80.63%, 67.70%, and 46.45%, respectively. The thermal conductivity behaviour tends to increase when SiO₂ nanoparticles are dispersed into the pure lubricant, compared to the pure PVE lubricant and previous studies. These findings indicate that SiO₂/PVE nanolubricant produces a significant increase in thermal conductivity, resulting in accelerated heat transfer, reduced friction and wear, and ultimately leading to increased energy efficiency and improved overall system performance.

This article presents an energy analysis of the UH-60 Black Hawk helicopter main rotor at a constant speed of 258 RPM for two blade configurations: the base (S₀) and modified (S₂) ones. Using calculated data and CFD modeling results, a comparison of the thrust (Cₜ), power (Cₚ), and integral efficiency (FM) coefficients is performed. It is found that when switching from S₀ to S₂, the power coefficient decreases by 39.5%, and the efficiency index increases by 60.4%, with virtually unchanged thrust. An analysis of the pressure and velocity distributions confirms a reduction in induced losses and equalization of the flow field behind the rotor. The results demonstrate that geometric optimization of the blade provides a significant increase in energy efficiency without increasing the speed and without losing the lifting capacity, which opens up prospects for further improvement of the rotor systems of medium-class helicopters.

The efficiency of energy saving in rural electric networks with a voltage of 0.38 kV is an important task, especially in conditions of asymmetric load. The article discusses the main causes of load asymmetry, their impact on electricity losses and a decrease in the quality of electricity supply. Methods and technical solutions aimed at increasing energy efficiency and reducing electricity losses are proposed. The possibilities of introducing modern digital technologies for monitoring and load management, as well as promising areas for the development of rural electric networks, taking into account the requirements of energy efficiency and sustainability of energy systems, are being considered. This paper examines the main causes of asymmetry, its impact on energy consumption and network parameters, and suggests technical solutions to improve energy efficiency in rural electric networks.

Abstract The EU has embarked on an ambitious path toward climate neutrality. How difficult will this transition be for the population as a whole and different subsets of consumers? This paper investigates this question using a dynamic general equilibrium model that captures a key feature of energy consumption: the relative energy content in one’s consumption basket falls significantly as a function of one’s relative income. Thus, low-income consumers are expected to be hit harder by the higher energy prices that we anticipate over the next few decades. In the model, energy—a complementary input to capital and labour—can be produced either using fossil fuel or a “green” technology. We represent the EU policy in terms of a tax on fossil fuel and show that the European Commission’s Fit-for-55 package implies a 106.4% tax on the fossil-based technology. The output losses from this tax are substantial, and GDP is 6.3% lower in the new steady state. The burden falls primarily on the lowest-income agent who represents the first income quintile and is 47% more worse off than the highest-income agent representing the fifth quintile. The output losses can almost be cut in half if the economy achieves a simultaneous increase in energy efficiency as outlined in the Fit-for-55 package.