Energy-efficient Applications Research Articles

Enhanced energy recovery in municipal wastewater treatment plants through co-digestion by anaerobic membrane bioreactors: current status and future perspectives

AbstractToday, the transition to renewable energy from conventional energy practices is more important than ever to establish energy security and mitigate climate change. The wastewater treatment plants (WWTP) consume a remarkable amount of energy and cause significant greenhouse gas emissions. The energy balance of WWTP can be improved by implementing energy-efficient applications such as anaerobic digestion. However, most of the existing WWTPs utilize only sewage sludge in conventional anaerobic digesters (CAD) which results in low biogas generation. Generally, co-digestion is indicated as an effective solution for the low biogas generation faced in mono-digestion. Moreover, recently, anaerobic membrane bioreactors (AnMBR) have been promoted as a prominent alternative to CADs. This paper overviews the current situation of co-digestion applications by AnMBRs for municipal WWTPs. Furthermore, the environmental and economic aspects of these applications were reviewed. Lastly, challenges and future perspectives related to the co-digestion applications by AnMBR were thoroughly discussed. Graphical Abstract

Synergistic magnetoelectric enhancement in 0-3 particulate multiferroic composites: unveiling the exceptional interplay of Ba0.85Sm0.15TiO3 and Co0.85Sm0.15Fe2O4 phases for superior energy conversion.

This study investigates the complex investigation of the 0-3 particulate multiferroic properties found in composite materials. The materials used in this study are (1 - x)Ba0.85Sm0.15TiO3 (SmBT)-xCo0.85Sm0.15Fe2O4 (SmCF), and the research utilizes a combination of the solid-state reaction method and mechanical milling techniques. A cubic spinel secondary phase was discovered in Co0.85Sm0.15Fe2O4, while a tetragonal structure was found in Ba0.85Sm0.15TiO3. The M-H loops clearly indicate the presence of exchange interactions between spins with varying orientations within the domains. As the proportion of SmCF in the composites increased, the saturation magnetization and magnetic moments became stronger, indicating a greater level of exchange interactions. Through a temperature-dependent analysis, an increase was observed in both the dielectric constant (εr) and dielectric loss (tan δ). Nevertheless, there was a decrease in εr above the Curie temperature. It is worth mentioning that there was a significant increase in the magnetoelectric coupling constant, suggesting a stronger interaction between magnetic and electric fields. This increased interaction leads to a more effective conversion of electrical energy into its magnetic equivalent, indicating a significant improvement in overall energy efficiency. The results of our study shed light on a promising direction for the development of advanced multifunctional materials, which could have significant implications for energy-efficient applications.

Do Opportunity Costs of Regulations Appropriately Benefit or Inappropriately Burden Disadvantaged Consumers?

Abstract President Biden’s first-day memo “Modernizing Regulatory Review” directs the Office of Management and Budget to “propose procedures that take into account the distributional consequences of regulations… to ensure that regulatory initiatives appropriately benefit and do not inappropriately burden disadvantaged, vulnerable, or marginalized communities.” This paper makes two contributions. First, it discusses how economic analysis can transparently provide the information needed to make value-judgments about what distributional effects are appropriate and inappropriate. Second, it discusses the distributional consequences of regulations that are either designed to reduce internalities or might have the additional benefit of reducing internalities. Examples include tobacco product regulations, appliance energy efficiency standards, and automobile fuel efficiency standards. In many cases, the regulations will increase the prices or decrease the availability of goods that disadvantaged consumers prefer. This paper discussed how to determine whether restricting their consumption opportunities creates net benefits or net costs for disadvantaged consumers. Inframarginal consumers who do not change their consumption face higher opportunity costs but do not receive any benefits from reduced internalities. Empirical challenges include the need to quantify the fraction of inframarginal consumers and the size of the internalities.

Enhancing thermal performance in enclosures filled with nanofluids subjected to sinusoidal heating: a numerical study

ABSTRACT This study conducts a comprehensive numerical investigation into enhancing thermal transfer within square enclosures filled with water-based oxide nanoparticle suspensions, subjected to central sinusoidal heating. Further flow configuration, influenced by an inclined magnetic field, is designed with a focus on enhancing thermal efficiency for engineering applications. Key innovations include the application of sinusoidal heating elements to enhance thermal performance significantly. Computational analysis supported by finite element analysis, quantifies the impact of these parameters on flow dynamics and thermal transmission, presenting a substantial advance in the understanding of nanofluid-filled enclosure thermal management. The study reveals that the undulation of the heating element plays a crucial role in the heat transfer rate, with improvements observed as undulation increases. The introduction of magnetic fields further controls flow distribution and buoyancy effects, as demonstrated by our findings that an increase in the Rayleigh number correlates with enhanced convection, dominating the cavity's thermal dynamics. Additionally, the report outlines the conditions under which the Nusselt number increases, indicating enhanced thermal performance. These insights are pivotal for designing optimized heat transfer systems and energy-efficient applications, setting a new benchmark for thermal management strategies in practical engineering contexts.

Achieving net negative sensible heat release from buildings

Heat is added to the surroundings as a result of replacing natural landscapes with buildings. This includes waste heat from air conditioning systems and heat transferred into the environment from exterior surfaces. Here, we propose a new concept of “negative sensible heat release” from buildings—that is, buildings that put less sensible heat into the environment than that released from the unbuilt terrain upon which the building was constructed. We explore the potential for net negative sensible heat releasing buildings through simulation studies in hot arid and humid cities—Phoenix, and Houston. Results show that it is possible to achieve net negative sensible heat release from low-rise office buildings by simply increasing roof and wall solar reflectance using existing technologies. While typical 2-story office buildings can generate average heat fluxes of around 100 W/m2 (based on building footprint area), by increasing solar reflectance of the roof from 0.2 to 0.9 and solar reflectance of the walls from 0.2 to 0.65, the same building can generate net negative sensible heating of 20 to 40 W/m2. Increasing building insulation and energy efficiency of appliances and air conditioning equipment can further reduce the heat release from buildings. This points to a compelling mechanism whereby buildings can be designed or retrofitted to have a beneficial impact on the local thermal environment.

A study on creating energy efficient cloud-connected user applications using the RMVRVM paradigm

Many applications that run on smartphones are heavy on User Interface (UI) and depend on back-end services deployed on the cloud to fetch the required data through REST-based API. Because of the large number of devices actively being used, their collective energy consumption is very significant. Saving energy on these devices is beneficial not only for reducing the carbon footprint but also for the end users as it results in longer battery life. The data fetched by these applications using the REST API is generally processed, filtered and made compliant with the user interface through a paradigm called the Model View View-Model (MVVM).In our previous work Singh (2022a), we proposed a novel Remote-Model View Remote-View-Model (RMVRVM) paradigm to reduce battery consumption by MVVM-based UI-centric cloud-connected applications. In this paper, we present new results and details of the architecture and properties of the RMVRVM paradigm, discuss the complexity shift, provide a migration framework to help practitioners migrate the existing MVVM-based applications and also discuss the possibility of RMVRVM replacing MVVM. We apply the migration framework on an open-source MVVM application and run the experiment to prove the efficacy of RMVRVM. We also expanded the experiments to include the iOS platform and 4G network. To cover the complexity shift to server-side, we discuss the energy consumption on the cloud and how energy-saving practices in cloud data centers help save overall energy consumption.

LateSearching for the most energy-efficient composition of a mixture of dimethyl ether and carbon dioxide as an air conditioning system refrigerantr

BACKGROUND: Carbon dioxide can be an alternative refrigerant for vapor compression refrigeration systems, particularly air conditioning systems (ACSs). However, its use suffers from the increased pressure in the refrigeration circuit. To solve this, for its reduction, a mixture of CO2 with a substance that has significantly lower pressures under the same conditions can be developed, for example, dimethyl ether (DME), which has zero GWP and ODP, is inexpensive and readily available. The study of DME, in particular, was conducted by the Department E4 “Refrigeration and Cryogenic Engineering, Air Conditioning and Life Support Systems” of N.E. Bauman Moscow State Technical University. DME is moderately toxic and flammable.
 AIM: This study aims to investigate the possible use of a mixture of DME and carbon dioxide for energy-efficient application in ACSs using commercially available compressors for R410A.
 METHODS: Comparative calculation analysis of the characteristics of a simple one-stage vapor compression cycle was performed using R410A and a mixture of DME and CO2 using the calculation packages Mathcad 15, Aspen HYSYS v. 10, SOLKANE8, and REFPROP.
 RESULTS: 1. The cycle on pure DME is the most effective in terms of the coefficient of performance: ε = 5.63 at an ambient air temperature of 26°C, ε = 3.07 at 40°C. 2. It is necessary to consider the influence of temperature glides, the average value of which ranges from 10°C to 30°C depending on the concentration of components. 3. At DME/CO2 ratios of 40/60% and 60/40% (in mole fraction), the discharge pressure corresponds to the discharge pressure in the R410A cycle, with 39.62 bar at an ambient temperature of 26°C and 37 bar at 40°C, respectively.
 CONCLUSIONS: An environmentally friendly mixture of DME and CO2 with low GWP and zero ODP is developed. An increase in the percentage of DME in the mixture increases the coefficient of performance and reduces the pressure range, and at the same time, significant temperature glides arise, which affects the installation efficiency, namely, the transition to a cycle with a receiver tank, i.e., with a recuperative heat exchanger between the fluorinated refrigerant flow leaving the evaporator and the fluorinated refrigerant flow leaving the condenser. The developed mixture is less efficient than the R410A refrigerant in terms of the coefficient of performance and discharge pressure. However, it is possible to further consider a mixture of DME and CO2 with concentrations of 40% and 60%, respectively, as a replacement for the R410 refrigerant because there is a correspondence of discharge pressures for serial compressors (about 40 bar); however, it is necessary to keep in mind the flammability risk of the mixture.

Hetero-Structure Junctionless MOSFET with High-k Corner Spacer for High-Speed and Energy-Efficient Applications

In this research work, Hetero-structure Junction-less MOSFET having a Silicon-Germanium source and high-k inner corner spacer is proposed and investigated. In this article, we have shown that the introduction of a high-k dielectric material in the inner corner spacer and a low-k dielectric material in the rest of the spacer in the optimally designed device leads to a substantial reduction in parasitic capacitances, resulting in higher operating speed. It was also shown that proper doping in the drain-source underlaps regime, can improve the short channel performance (SCP) of the device by increasing the effective gate length. The optimally designed proposed device produces on current (ION) ~0.33 mA and off current (IOFF) ~ 5.55 fA along with ION/IOFF=6.08x1010, Subthreshold slope (SS)=59.6 mV/decade and drain induced barrier lowering (DIBL)=82.2 mV/V. This paper also highlights the performance improvement of the proposed device in terms of both speed and energy consumption, as compared to that of Junctionless Double Gate MOSFET when implemented as logic gates.

Unveiling Nanogranular Advancements in Nickel-Doped Tungsten Oxide for Superior Electrochromic Performance

Electrochromic materials allow for precise control of their optical properties by applying an electric field, which has led to recent developments in energy-saving and indoor temperature control systems like smart windows. The selective incorporation of metal dopants is an effective technique for generating highly advanced semiconducting metal oxides with precisely customized physicochemical characteristics. In this report, we employed a one-step electrodeposition process to fabricate nickel-doped tungsten oxide (W–Ni) thin films, systematically probing the impact of nickel (Ni) doping on the collective material characteristics. Comprehensive X-ray diffraction research revealed significant changes in diffraction patterns, suggesting slight modifications in the structure caused by Ni doping. The scanning electron microscopy showed complex differences in the microstructure of the film, such as a dense surface, porosity, and clustering of nanogranules. The WNi-3% thin film doped at 3 wt. % exhibited excellent electrochromic performance by efficiently handling lithium ions and displaying favorable electrochromic properties. The improved electrode, WNi-3%, showed a maximum optical modulation of 81.90%, exceptional reversibility of 99.4%, and a high coloration efficiency of 75.12 cm2/C. These findings underscore the efficacy of Ni-doping in tailoring the electrochromic properties of nickel-doped tungsten oxide thin films, thereby advancing the frontiers of high-performance electrochromic materials for energy-efficient applications.

CMOS full adder cells based on modified full swing restored complementary pass transistor logic for energy efficient high speed arithmetic applications

In modern Digital System design, adders are widely used in many applications including Microprocessors, Digital Signal Processors, Arithmetic Logic Units and digital signal processing. Power efficiency is an important key factor for any integrated circuits. By considering the importance of Full Adder (FA) cells, their power consumption may play significant role in overall power consumption. So designing a low-power full adder is important to achieve the high-performance computing. Swing restored technique is commonly used method to reduce the signal swing at the internal nodes and it helps to reduce the power consumption and improves the circuit's speed. This paper presents a novel hybrid full adder cell design using the modified swing restored technique and complementary pass transistor logic. The Full Adder circuit was implemented using Cadence Virtuoso tool on gptk 180nm CMOS process technology. The proposed full adder was compared with earlier reported circuits based on Delay, Power and PDP. The comparison shows that proposed circuit consumes less power with high performance. Also various process corners and noise immunity were analyzed to find the sensitivity of the circuit. Further an 8-bit Ripple Carry Adder was designed using the proposed full adder to verify the functionality in higher order bits. Simulations were performed and analysed using the Cadence Spectre.

A 0.6 V voltage reference circuit with 57 ppm/°C temperature coefficient, 73 KΩ output impedance and 0.080%/V line sensitivity for energy efficient applications

In this paper, a voltage reference circuit generating 0.6 V developed in the Semiconductor Laboratory (SCL) 0.18 μm standard CMOS technology has been presented. It is based on the principle of Beta multiplier circuit. Operating under a supply voltage of 1.8V, the proposed reference accomplishes a line sensitivity as low as 0.080%/V across a voltage range of 1.8 V to 3.5 V. In addition to a low line sensitivity, it achieves a low temperature coefficient of 57 ppm/ °C over the temperature range of −40 °C to +85 °C. The circuit furnishes a power supply rejection ratio (PSRR) of −75.72 dB. The improved load regulation feature allows the circuit to drive loads as low as 73 KΩ with minimum variation. A reliable nature of the circuit has been observed on examining the response for different process corners and variations.

Magneto-ionic modulation of the interlayer exchange interaction in synthetic antiferromagnets

The electric-field control of magnetism is a highly promising and potentially effective approach for realizing energy-efficient applications. Recent interest has focused on the magneto-ionic effect in synthetic antiferromagnets, driven by its potential to enable high-density data storage devices with ultra-low power consumption. However, the underlying mechanism responsible for the magneto-ionic effect on the interlayer exchange coupling remains elusive. In our work, we find that the modulation of the interlayer exchange coupling is highly sensitive to the thickness of the ferromagnetic layer. We have identified that the changes in the interlayer exchange coupling induced by the gate voltage can be associated with the magneto-ionic effects on the top ferromagnetic layer of the synthetic antiferromagnet. The direct contact between the high ion mobility oxide and the top ferromagnetic layer plays a crucial role in facilitating these effects, largely modifying the anisotropy of the layers. Our findings highlight the important role of magneto-ionic control over the properties of the top ferromagnetic layer in governing the observed modifications in the interlayer exchange coupling. This study provides crucial insight into the intricate interplay between stack structure and magneto-ionic effect on magnetic properties in synthetic antiferromagnetic thin film systems.

Optimizing workload distribution in Fog-Cloud ecosystem: A JAYA based meta-heuristic for energy-efficient applications

Fog-integrated Cloud has emerged as a novel computing paradigm that brings Cloud computing services to the network's edge in real-time, though with limited capabilities. Despite its advantages, there are several challenges including workload distribution, energy consumption, computational time, and network latency, that require attention. The workload of IoT applications can be distributed over the Fog or Cloud devices based on their priority, deadline, and latency restrictions. In this work, we introduce a novel population-based metaheuristic called MAYA, a modified variant of the JAYA algorithm, to address the Energy-Efficient Workload Distribution of Sensors (EEWDS) in the Fog-Cloud ecosystem. The workload distribution of IoT applications depends on several factors such as request deadlines, the energy consumed during transmission, and needed computation. The performance of the proposed model for the energy consumption, computation time, CO2 emission, fairness index, and the convergence rate, is evaluated through simulation experiments. The results are compared in two scenarios: one concerning to methodology, where the performance is compared with JAYA, Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and Ant Colony Optimization (ACO) techniques. The other scenario is based on the environment, where we examine Cloud-only, Fog-only, and Fog-Cloud integrated environments. Compared to JAYA, GA, PSO and ACO, the proposed MAYA technique demonstrates significant improvements, including reduction in energy consumption by 34.76%, 88.92%, 85.36% and 93.84%; decrease in computation time by 37.64%, 85.07%, 87.22%, and 91.08%; decrease in CO2 emissions by 23.46%, 76.24%, 97.17%, and 99.02%; and increase in fairness index by 9.62%, 3.72%, 16.90%, and 15.26% respectively.

Nanostructure engineering of ruthenium-modified electrocatalysts for efficient electrocatalytic water splitting

This review provides a systematic summary of the nanostructure engineering of Ru-modified electrocatalysts for the electrocatalytic water splitting. These regulation strategies, such as single atom sites, doping, alloying and interfacial engineering are summarized in detail.

A black electrochromic device based on a CuI film for energy-efficient applications

An electrochromic device based on a CuI film has been designed and fabricated, which increases the content of Cu ions in the device. The device shows excellent bistability and optical modulation ability after parameter optimization.

Photonic reservoir computing for energy efficient and versatile machine learning application

Time-multiplexed reservoir computing is a machine learning concept which can be realised in photonic hardware systems using only one physical node. The concept can be used for various problems, ranging from classification problems to time-series prediction tasks, while being fast and energy efficient. Here, a theoretical analysis of a reservoir computer realised via delay-coupled semiconductor lasers is presented and the role of the internal system time-scales and the bifurcation structure is discussed. It is further shown that optimal performance can be reached by tailoring the coupling delays to the specific memory requirements of the given task.

Static and dynamic magnetization control of extrinsic multiferroics by the converse magneto-photostrictive effect

Using strain to control magnetic properties through anisotropy changes is a method to create functional materials with energy efficient applications. The strain can be inferred remotely by the light-induced non-thermal dimension change of materials named the photostrictive effect. Still, the control of dynamic magnetic properties via this effect is pursued. The need of a physical quantity to encompass and to describe anisotropic magnetization changes under the photostrictive effect is also remaining. Here, the photostrictive effect with visible light is used to engineer static and dynamic magnetic properties in a multiferroic material. A converse magneto-photostrictive coupling coefficient is also proposed as a physical quantity to assess anisotropic magnetization changes under this effect. These results provide a path towards understanding light-induced magnetization changes and a potential to be used in wireless approaches for the control of magnetic properties and tunable RF/microwave devices.

Fabrication of Z-scheme ZnO/g-C3N4/ZnS nanocomposites using high power laser for methylene blue degradation

Photocatalysis plays a vital role in addressing environmental challenges by harnessing solar energy for efficient pollutant degradation. In this study, we investigate the photocatalytic activity of a ZnO/g-C3N4/ZnS composite system in the degradation of methylene blue, a widely used dye with detrimental effects on aquatic ecosystems. The composite materials were synthesized using a facile and scalable approach, and their structural properties, morphologies, sizes, and elemental compositions were characterized using different analytical techniques. The ZnO/g-C3N4/ZnS composite exhibited enhanced photocatalytic performance compared to individual components. Remarkably, the degradation efficiency reached 80% for the composite with a 30% ZnO composition, surpassing the efficiencies of ZnS alone (29%) and ZnS/g-C3N4 (65%). The composite’s higher degradation efficiency is due to synergistic semiconductor effects, enhancing charge transfer and reducing electron–hole recombination. ZnO incorporation increases active sites and surface area, improving interaction with methylene blue. The favorable band edge positions of ZnO aligned with ZnS and g-C3N4, facilitating the utilization of a broader spectrum of solar light. The composite’s photocatalytic activity was achieved under UV light irradiation, demonstrating its potential for sustainable and energy-efficient applications. This study highlights the significance of composite design and the Z-scheme concept in photocatalysis, offering insights into the development of advanced materials for environmental remediation. The findings contribute to the understanding of efficient solar-driven pollutant degradation and pave the way for the design and optimization of innovative photocatalytic systems for sustainable environmental solutions.

Design and Optimization of a CMOS-based 4-bit Absolute Value Detector

This research paper introduces a meticulously crafted blueprint for a 4-bit Absolute Value Detector (AVD) utilizing cutting-edge Complementary Metal-Oxide-Semiconductor (CMOS) technology. The proposed architectural marvel has been specifically fine-tuned to cater to the demands of high-speed, energy-efficient applications, making it applicable across a wide spectrum of signal-processing domains. At its core, this design harnesses the synergistic power of multiplexers, a ripple carry adder, and a comparator, strategically orchestrated to swiftly and accurately determine the absolute magnitude of the input signal, subsequently comparing it against a predefined threshold. The resultant circuit stands as a testament to its prowess, boasting a remarkably low latency while maintaining commendably low power consumption and a robust resistance to external noise interference. In doing so, it not only aligns itself with the contemporary requirements of rapid real-time signal processing but also paves the way for scalability, positioning itself as a viable solution for more intricate and demanding applications. By doing so, this innovation not only contributes to the ongoing evolution of electronic technologies but also sets the stage for future research endeavors, promising a brighter and more sophisticated future for the field.

Research on Energy-Efficient Disc Pumps: A Review on Physical Models and Energy Efficiency

Disc pumps have obvious advantages in dealing with difficult-to-pump media. Energy efficiency and sustainable energy management are important topics with regard to reducing costs and promoting carbon neutrality. Though the concept of the disc pump was proposed in the 1850s, development was slow and limited by its initial model. However, with the development of industries such as petrochemicals and food, the efficient pumping of difficult-to-pump media is much needed, but facing challenges. Therefore, research on energy-efficient disc pumps is particularly important moving forward. In this paper, the available information from the open literature about the research and development of the disc pump will be thoroughly reviewed. It focuses on the historical development, energy efficiency and physical model application of the disc pump. The review ends with a proposal for the direction of future development, and in this aspect, it is proposed that the energy efficiency prediction model based on velocity slip theory, the energy management system based on multi-scenarios and the design method based on energy conversion theory are important. The latest achievements in energy conversion are given. This review also provides a new perspective for the development of energy-efficient disc pumps.