Hasil untuk "Energy conservation"

C. Farhat, M. Lesoinne, P. Tallec

Rajalakshmi K, R. Thirumalai Selvi

The building industry, which uses the most electricity, has a significant potential to contribute to energy consumption reduction. Commercial structures use more energy than other types of structures because of their productive and logistic features. In these types of structures, one of the main energy consumers is the HVAC system which comprises of heating, ventilation, and air conditioning, especially in arid conditions. Energy-efficient environment friendly HVAC system conception and execution can significantly lower the use of energy and support ecologically sound growth in business establishments. On the other hand, inadequate implementation of methods for reducing energy use may lead to a decline in the welfare of the environment. Therefore, in order to achieve energy efficiency and maintain the optimum degree of temperature regulation, a comprehensive energy conservation strategy is needed. To accomplish this goal, model predictive control strategy-based methodologies are used in this work. To estimate how much energy will be used in commercial buildings, four deep learning-based methods are utilised: radial basis function networks, multi-layer perceptrons, artificial neural networks, and back propagation neural networks. To further cut down on energy use, four distinct control mechanisms are used. The performance of the suggested solution is examined using performance measures like Mean Absolute Error and Mean Absolute Percentage Error.

Kylee Fleckenstein, Adam Stein, Heather L. Bateman et al.

The need for renewable energy has become increasingly evident in response to the climate change crisis, presenting a paradoxical challenge to biodiversity conservation. The Southwest United States is desirable for large-scale solar energy development (SED) due to its high global horizontal irradiance (GHI) values and vast open landscapes. However, this region is also rich in unique ecological and biological diversity. Several distinct species have garnered special attention as human population growth, habitat alteration, and climate change have accelerated in recent decades (i.e., LeConte’s Thrasher (Toxostoma lecontei), Bendire’s Thrasher (Toxostoma bendirei), Sonoran Desert Tortoise (Gopherus morafkai), Mojave Desert Tortoise (Gopherus agassizii), and the Southwestern population of the Burrowing Owl (Athene cunicularia). As the United States prepares to increase its development in renewable energies, particularly solar energy, there has been a growing concern about how this development will further impact these species. In this study, we propose a novel combined approach to find areas of high habitat suitability for endangered species within areas of high SED potential. Specifically, we employed species distribution modeling (SDM) to identify areas with suitable habitats and likely species presence, and we conducted a site suitability analysis for potential SED locations within the Southwest. As a result, we found significant overlap between potential SED locations and the high-priority habitats of all target species, thus underlining the importance of prioritizing conservation efforts as more solar projects are reviewed in these Southwestern states. Our study aims to inform conservationists and developers in making sustainable decisions for the region’s future development.

Perseverance Dzikunu, Eugene Sefa Appiah, Emmanuel Kwesi Arthur et al.

Abstract The increasing demand for cost-effective materials for energy storage devices has prompted investigations into diverse waste derived electrode materials for supercapacitors (SCs) application. This review examines advancements in converting waste into carbon-based SCs for renewable energy storage. In this context, different carbon-based waste precursor sources have been explored over the years as electrodes in SCs. These waste sources comprise of industrial, plastics and biowastes, including plant and animal wastes. The energy storage capabilities of the various waste derived SCs electrodes are highlighted to provide an understanding into the unique features that make them applicable to SCs. In addition, some challenges associated with the waste-derived SCs electrodes in terms of energy storage have been emphasized. Here, we also provided insights into the recent progress in SCs electrode synthesis techniques and their effects on electrochemical performance. SCs performance tailoring with material structures through the incorporation of different materials to form composites and optimized synthesis methods is an effective strategy. Hence, the synthesis methods outlined include pyrolysis, hydrothermal, microwave-assisted, template-assisted, and sol–gel techniques. The effect of the various synthesis methods on SCs performance has also been discussed. Overall, this review highlights waste valorization with future research directions and scaling challenges.

Kunal Bahuguna, Ramesh Kolluru, S. V. Raghurama Rao

This paper presents a novel structure-preserving scheme for Euler equations, focusing on the numerical conservation of entropy and kinetic energy. Explicit flux functions engineered to conserve entropy are introduced within the finite-volume framework. Further, discrete kinetic energy conservation too is introduced. A systematic inquiry is presented, commencing with an overview of numerical entropy conservation and formulation of entropy-conserving and kinetic energy-preserving fluxes, followed by the study of their properties and efficacy. A novelty introduced is to associate numerical entropy conservation to the discretization of the energy conservation equation. Furthermore, an entropy-stable shock-capturing diffusion method and a hybrid approach utilizing the entropy distance to manage smooth regions effectively are also introduced. The addition of artificial viscosity in appropriate regions ensures entropy generation sufficient to prevent numerical instabilities. Various test cases, showcasing the efficacy and stability of the proposed methodology, are presented.

Sheila M.W. Reddy, J. Montambault, Y. Masuda et al.

Behavioral sciences can advance conservation by systematically identifying behavioral barriers to conservation and how to best overcome them. Behavioral sciences have informed policy in many other realms (e.g., health, savings), but they are a largely untapped resource for conservation. We propose a set of guiding questions for applying behavioral insights to conservation policy. These questions help define the conservation problem as a behavior change problem, understand behavioral mechanisms and identify appropriate approaches for behavior change (awareness, incentives, nudges), and evaluate and adapt approaches based on new behavioral insights. We provide a foundation for the questions by synthesizing a wide range of behavior change models and evidence related to littering, water and energy conservation, and land management. We also discuss the methodology and data needed to answer these questions. We illustrate how these questions have been answered in practice to inform efforts to promote conservation for climate risk reduction. Although more comprehensive research programs to answer these questions are needed, some insights are emerging. Integrating two or more behavior change approaches that target multiple, context‐dependent factors may be most successful; however, caution must be taken to avoid approaches that could undermine one another (e.g., economic incentives crowding out intrinsic incentives).

P. Constantin, E. Weinan, E. Titi

WANG Huating, CHEN Heng, XU Gang et al.

The energy saving and emission reduction transformation of thermal power enterprises can reduce the coal consumption of thermal power supply, and then effectively reduce the growth of carbon dioxide emissions, which is of great significance to achieve the goal of carbon peak and carbon neutralization. Taking a 630 MW unit as an example, the system units of four waste heat utilization schemes (low-temperature economizer scheme, secondary low-temperature economizer scheme, bypass flue scheme and turbine boiler coupling scheme) were compared, and the key technical parameters and power saving effect were compared and analyzed. Moreover, a reference for the upgrading and technical transformation of energy conservation and emission reduction in China’s power industry was put forward. The results show that the exhaust gas temperature is reduced to 90 ℃, The coal consumption rate of power supply is reduced by 1.88 g/(kW⋅h) in the low-temperature economizer scheme, 2.16 g/(kW⋅h) in the secondary low-temperature economizer scheme, 2.29 g/(kW⋅h) in the bypass flue scheme, and 2.66 g/(kW⋅h) in the turbine boiler coupling scheme.

Qiang Gao, Lanqian Yang, Zhengyu Shu et al.

Enhancing the energy efficiency of building envelopes is one of the key strategies for energy conservation and reducing consumption in buildings. This study employs numerical research methods to explore the impact of crucial factors such as solar cell coverage, air channel height, indoor relative humidity, and indoor wind speed on the power generation performance and thermal comfort of a photovoltaic (PV)—Trombe wall. The dynamic changes in optical and thermal performance and energy efficiency matching mechanisms of this system are also discussed in hot summer and warm winter regions. The research findings indicate that the periods of good thermal comfort and power generation efficiency for humans are from 9:00 to 17:00 in winter. In summer, these periods are from 5:00 to 8:00 as well as from 17:00 to 20:00. When the system height is 2 m, the electricity price for power supplied by the PV—Trombe wall system is 25% lower than the residential price, with an annual energy generation of 322.5 kWh/m² of solar panel, which can save USD 6.35 in costs. Moreover, an experiment is conducted to investigate the thermoelectric correlation by constructing a traditional Trombe wall and an external PV—Trombe wall. When the coverage reached 52.08%, the overall system efficiency was maximized. At a coverage of 78.12%, the system’s thermal efficiency was at its lowest, while the maximum power generation was 510.3 W. It can be seen that the PV—Trombe wall possesses good economic benefits and energy saving as well as emission reduction potential in hot summers and warm winters regions, and the smooth implementation of related works will effectively promote its applications and promotions.

David Wright, John T. Giblin, Jeffrey Hazboun

The recent evidence for a stochastic gravitational wave background (GWB) in the nanohertz band, announced by pulsar timing array (PTA) collaborations around the world, has been posited to be sourced by either a population of supermassive black holes binaries or perturbations of spacetime near the inflationary era, generated by a zoo of various new physical phenomena. Gravitational waves (GWs) from these latter models would be explained by extensions to the standard model of cosmology and possibly to the standard model of particle physics. While PTA datasets can be used to characterize the parameter spaces of these models, energy conservation and limits from the cosmic microwave background (CMB) can be used $\textit{a priori}$ to bound those parameter spaces. Here we demonstrate that taking a simple rule for energy conservation and using CMB bounds on the radiation energy density can set stringent limits on the parameters for these models.

Luis Chacon, Guangye Chen

We consider the issue of strict, fully discrete \emph{local} energy conservation for a whole class of fully implicit local-charge- and global-energy-conserving particle-in-cell (PIC) algorithms. Earlier studies demonstrated these algorithms feature strict global energy conservation. However, whether a local energy conservation theorem exists (in which the local energy update is governed by a flux balance equation at every mesh cell) for these schemes is unclear. In this study, we show that a local energy conservation theorem indeed exists. We begin our analysis with the 1D electrostatic PIC model without orbit-averaging, and then generalize our conclusions to account for orbit averaging, multiple dimensions, and electromagnetic models (Darwin). In all cases, a temporally, spatially, and particle-discrete local energy conservation theorem is shown to exist, proving that these formulations (as originally proposed in the literature), in addition to being locally charge conserving, are strictly locally energy conserving as well. In contrast to earlier proofs of local conservation in the literature \citep{xiao2017local}, which only considered continuum time, our result is valid for the fully implicit time-discrete version of all models, including important features such as orbit averaging. We demonstrate the local-energy-conservation property numerically with a paradigmatic numerical example.

Chuan Li, Qi Li, Ruihuan Ge

This work concerns the melting performance enhancement in a finned shell and tube thermal energy storage device containing salt based phase change materials. Two storage materials of a pure nitrate salt and a nitrate salt based composite that made of nitrate salt, vermiculite and graphite were employed and comparatively investigated. A two-dimensional mathematical model was established to predict the heat transfer occurred in the salts by considering the combined impacts of natural convection and thermal conduction. A set of simulation data from literature was used to verify the modelling code for the pure salt and an experiment was built to validate the numerical model for the salt composite. The effects of fin amount, arrangement, length and thickness as well as operating condition on the device melting behaviour were detailedly evaluated. The results indicated the benefit of employment fins in accelerating the salt melting rate. The use of salt based composite combined with enhanced fins led to a more remarkable improvement on the device melting process, and the adjustment of fin length and thickness as well as composite ingredients composition achieved further intensification. For a given fin amounts over 0–8 with the same neighbour angle, the melting process in the device containing salt composite is respectively shortened around 79% and 56% compared to the device containing pure salt, indicating the utilization of composite is a better choice than the pure salt for the performance enhancement in finned shell and tube thermal energy storage device.

Shaoyun Zhang, Manli Sun, Qinglin Guo et al.

Natural hydraulic lime (NHL) can be used as an inorganic cementitious material, as it exhibits low shrinkage, salt-alkali resistance, moderate strength, and good durability with cultural relics. There has been increasing interest in NHL, as it is considered an appropriate material for the restoration and reinforcement of architectural cultural relics. In this study, limestone and potassium feldspar were mixed and calcined at different ratios and high temperatures, and artificial hydraulic lime (HL) was produced. According to the X-ray diffraction (XRD) results, the resulting products after high-temperature calcination were mainly composed of calcium oxide, dicalcium silicate (C₂S), and dicalcium aluminosilicate (C₂AS). As a compromise, when potassium feldspar accounted for 30% of the total mass, HL contains a more suitable air-hardening component and hydraulic component. Scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS) analyses show that the phases of calcium carbonate (CaCO₃) and hydrated calcium silicate (C-S-H) gradually increased with prolonged curing time for HL. To study the partial mechanical properties and durability of HL, a comparison was made with NHL. The mechanical properties were investigated with the flexural and compressive strengths and shrinkage. The results show that HL has higher strength than NHL, but NHL has smaller shrinkage. Accelerated aging tests indicated that HL and NHL5 led to higher resistance to water immersion, fluctuations in temperature and humidity, sulphate decay, an alkali environment, and frost–thaw action than NHL2. HL has excellent mechanical properties and durability and can be considered a conservation material for stone relics in the future.

Vedat Tanriverdi

In some cases, it is possible to show the conservation of energy by using equations of motion in mechanics. By considering these results, some people can think that the conservation of energy is the result of equations of motion or Newton's second law. If we consider the conservation of energy by itself, it is valid for nearly all natural sciences and more general than equations of motion. From this perspective, it is not totally convenient to say that the conservation of energy is the result of equations of motion. It is clear that there can be a relation between them, but it is not explicit enough. In this study, we have studied the relationship between the conservation of energy and equations of motion. And, the study revealed a subtle difference between them in mechanics which can be used to experimentally test which explains the nature best or to better understand the relation between them.

Shuai Wang, Zhi Wen, Ruifeng Dou et al.

Slag mixing technique is a process that eliminates the lumping phenomenon of slag and iron in desulfurization slag. This process is conducted by mixing the high-temperature converter slag and iron desulfurization slag. The slag crushing difficulty is remarkably reduced after mixing. This technique eliminates the lumping phenomenon in the iron desulfurization slag. A numerical model based on Eulerian multiphase flow was established for the mixing process. The model obtained the characteristics of the phase field distribution inside the slag tank. The slag expansion phenomenon was identical with experimental results. A simplified temperature dropping model of slag mixing process was established based on the principle of energy conservation. According to this simplified model, the time dependence of the chemical reaction rate and temperature was investigated. The simplified model built by multifactor regression method can effectively predict the chemical reaction rate and temperature change under the following conditions: converter slag with an initial mass of 4–12 t, an initial iron oxide content of 20%–40%, an iron desulfurization slag mixing volume of 1–5 t, and an iron desulfurization slag mass flow rate of 0.1–1 t/s. The simplified model provides basic physical parameters for post-processing while ensuring safe production.

Thomas Villemin, Olivier Farges, Gilles Parent et al.

Xin Huang, Lin Qiu

Abstract To address the prominent problem of declining runoff in many rivers around the world, studying the law of runoff change and attribution analysis is very important for the planning and management of watershed water resources and has practical significance for solving the imbalance between supply and demand of watershed water resources and maintaining the healthy development of rivers. Three commonly used coupled water-energy balance equations based on Budyko hypothesis are selected to estimate the elasticity coefficient of runoff change to each driving factor, and the contribution rate of different factors to runoff change in the study area is quantified by the total differential method and the complementary method, respectively. The results show that the runoff of Huangfuchuan River basin showed a significant decreasing trend from 1954 to 2015, and the runoff mutation points were 1979 and 1996; in the alteration period I (1979–1996), precipitation was the main factor leading to the runoff reduction in Huangfuchuan River basin, followed by the influence of underlying surface; the contribution rate of underlying surface to runoff alterations ranged from 63.7% to 65.46%; the impact of potential evapotranspiration was slightly smaller. In the alteration period II (1997–2015), the underlying surface played a dominant role in runoff reduction of Huangfuchuan River basin. The contribution rate of the underlying surface to runoff change ranged from 80.21% to 86.34%, followed by precipitation, and the potential evapotranspiration had the least impact. The impact of human activities on the whole watershed increased with the passage of time. The land use change, the overall increase of NDVI (vegetation cover) and the construction of water conservation projects are important reasons for the reduction of runoff in Huangfuchuan River basin.

Al-Dabbagh Riadh

Population growth, social and industrial activities have increased significantly, resulting in an increase in the quantities of wastes in UAE in specific the Emirate of Ajman. Most of the waste is still not thoroughly treated and ends up in municipal landfills, where organic waste generates many gases such as methane, a potent greenhouse gas. Currently, little of the waste is burned, and the rate of municipal waste recycling has been rapidly rising. Waste management in the Ajman is coordinated through local authorities. For this purpose the UAE has set Key Performance Indicators (KPIs) to measure its performance against its targets of 2021. To support the national efforts, Ajman is continuously seeking to adopt vital initiatives and projects that are positively affecting all aspects of life. Waste issues are handled through recycling and converting waste to energy and resources, new technologies and improved waste separation and collection systems. Ajman Municipality and Planning Department has initiated plans and efforts in waste management, including converting waste to energy, treating wastewater, and controlling the movement of hazardous waste. The programs are implemented with the aim to reduce the adverse per capita environmental impact of the city, including by paying particular attention to air quality and all types of waste. The paper presents an overview of the waste situation and the management practices according to the Municipality's plans and strategies. It is concluded that Ajman still lacks an infrastructure for organic waste recycling for residents. This organic waste is a significant contributor to methane emissions from landfills. Challenges are to be solved, such as the lack of adequate waste sorting and recycling facilities in the Emirate and weak community culture to adopt waste sorting. Many practices started to be implemented by the Municipality, for instance, creating an incinerator used to treat non-chemical medical waste generated from hospitals & clinics. As a result, Ajman has witnessed a reduction in the quantity of waste dumped in the landfill.

Jianxu Liu, Heng Wang, Sanzidur Rahman et al.

Improving energy efficiency and conservation is integral to sustain agricultural growth in emerging economies. This paper investigates the energy efficiency and energy-saving potential of the agricultural sector of 27 emerging economies using a stochastic frontier approach and Shephard distance function, and their determinants are examined using the Tobit quantile regression model. Results revealed that energy efficiency in the agricultural sector fluctuated during the period from 1998 to 2017. The median average energy efficiency was estimated at 0.74, and the cumulative energy-saving potential was estimated at 542.80 million tons of oil equivalent (Mtoe), which can be achieved by eliminating energy inefficiency alone. Differences exist in energy efficiency and energy-saving potential across continents, with higher potential in Asia and lower potential in Europe. Economic structure, urbanization and GDP per capita have negative influences on agricultural energy efficiency. Energy mix and pesticide use are significant drivers of energy efficiency, while the ratio of agricultural land that has varied influences different quantiles. Policy implications include optimization of the energy mix, economic structure and pesticide use.