Comparison Of Energy Efficiency Research Articles

Enhancing Energy Efficiency of Cumene Production Through Reactor Output Recycling Modification in a Heat Exchanger

Cumene production generally involves irreversible and exothermic reactions that leads to an increase in product temperature and needs to be cooled for further processes. The high temperature of reactor product can be utilized as a heat transfer fluid in heat exchanger. This modification process is essential for improving energy efficiency by recycling the reactor output with high temperature as a heat transfer fluid, so that the implementation of replacing the heater with a heat exchanger can be carried out for the process of increasing the initial feed temperature. In an effort to enhance energy efficiency in the cumene production process, simulations were conducted using HYSYS and the comparison of energy efficiency for both basic and modified processes can be evidenced by comparing the total amount of energy required during the process. The results shows that the total amount of energy required for the modified process is 39,814,003.7 kJ/h, while for the basic process is 40,588,937.4 kJ/h, with a difference of 774,933.7299 kJ/h. Since the total amount of energy required in the modified process is smaller than the basic process, then the modification process will increase the energy efficiency of cumene production. Copyright © 2024 by Authors, Published by Universitas Diponegoro and BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

R-Blocks: an Energy-Efficient, Flexible, and Programmable CGRA

Emerging data-driven applications in the embedded, e-Health, and internet of things (IoT) domain require complex on-device signal analysis and data reduction to maximize energy efficiency on these energy-constrained devices. Coarse-grained reconfigurable architectures (CGRAs) have been proposed as a good compromise between flexibility and energy efficiency for ultra-low power (ULP) signal processing. Existing CGRAs are often specialized and domain-specific or can only accelerate simple kernels, which makes accelerating complete applications on a CGRA while maintaining high energy efficiency an open issue. Moreover, the lack of instruction set architecture (ISA) standardization across CGRAs makes code generation using current compiler technology a major challenge. This work introduces R-Blocks; a ULP CGRA with HW/SW co-design tool-flow based on the OpenASIP toolset. This CGRA is extremely flexible due to its well-established VLIW-SIMD execution model and support for flexible SIMD-processing, while maintaining an extremely high energy efficiency using software bypassing, optimized instruction delivery, and local scratchpad memories. R-Blocks is synthesized in a commercial 22-nm FD-SOI technology and achieves a full-system energy efficiency of 115 MOPS/mW on a common FFT benchmark, 1.45× higher than a highly tuned embedded RISC-V processor. Comparable energy efficiency is obtained on multiple complex workloads, making R-Blocks a promising acceleration target for general-purpose computing.

베이지안확률변경분석을 이용한 국내 철강기업의 에너지효율성 분석

Steel companies, due to their production processes, emit a large amount of greenhouse gases. Therefore, improving the energy efficiency of them is a very important issue in responding to climate change. The starting point for effective management of energy efficiency improvements in steel companies is the objective measurement of their energy efficiency. Previous studies primarily utilized traditional Stochastic Frontier Analysis to estimate the energy efficiency of steel companies. Meanwhile, Bayesian Stochastic Frontier Analysis, which incorporates Bayesian Inference into Stochastic Frontier Analysis, offers the advantage of more accurate and flexible estimates by considering the uncertainty of parameters. Despite the advantages, there has been no research applying Bayesian Stochastic Frontier Analysis to analyze the energy efficiency of Korean steel companies. This study is the first to apply Bayesian Stochastic Frontier Analysis to Korean steel companies, using the Gibbs Sampling technique to estimate the energy efficiency of 22 major Korean steel companies from 2011 to 2019. The key findings of this study are as follows: First, the overall average energy efficiency of steel companies is 0.5450. Second, from 2011 to 2013, the yearly average energy efficiency of the steel companies analyzed shows an improving trend, peaking in 2013, followed by a decreasing trend. Third, a comparison of average energy efficiency across individual companies reveals the firms with relatively high energy efficiency, exceeding 0.8

Energy Efficiency Comparison in Heating Water Using Gas, Electric, and Induction Cooktops and Determination of Container Emissivity Coefficient

A 1.315 kg stewpan is used to boil 1 kg water using three different type of cooktops, that is, gas, electric, and induction. The power of the electric cooktop is 600 W, a gas cooktop uses the maximum setting (large burner in control knob), and the induction cooktop has maximum power of 1200 W. We have observed two different settings of power: 600 W and 1200 W. In the first setting, we compared induction and electric cooktops, while in the second induction and gas cooktops were compared. We obtained energy efficiency about 67.24% and 56.2% for the first setting and 74.03% and 38.55% for the second, which shows that induction cooktop always gives better performance compared to the other cooktops. Besides this, we also investigated the energy leak from the stewpan to the environment through radiation, which should be the same, since all four observations were using the same container to heat the water.
 Keywords: energy efficiency, heating water, induction cooktops, container emissivity coefficient

Improving energy efficiency: a highly efficient coaxial design for a laser ranging system with a splicing lens.

Light detection and ranging (LiDAR) systems have made significant contributions in different applications. The laser ranging (LR) system is one of the core components of LiDARs. However, existing coaxial LR systems suffer from low energy efficiency due to obstruction of the reflection mirror. In this study, we carefully design a laser transmitter and receiver subsystem and consequently propose a highly energy-efficient coaxial design for a time of light-based LR system, where a perforated mirror and splicing lens account for the promotion of energy efficiency. The small hole in the perforated mirror is located on the object focus of the focusing lens to ensure the laser beam will pass through the perforated mirror without obstructions. The ring-shape splicing lens, consisting of two parts, is used for laser collimation and laser reception simultaneously. Laboratory experiments proved that the proposed design eliminates the complex calibration process for noncoaxial LR systems while reaching a comparable energy efficiency, which is higher than 98%. We believe it is an economical yet efficient way to promote the energy efficiency of coaxial LR systems.

Efisiensi Energi Berkelanjutan: Strategi Desain dan Perhitungan Optimalisasi Efisiensi Energi pada Selubung Bangunan

Global warming is an increase in the temperature of the Earth's surface over the last few decades. Building energy consumption is the number two contributor to global warming. About 5-13% of the energy consumed during construction and the remaining 87-95% occur during the lifetime of a building, mainly for heating, cooling, and lighting purposes. This requires the selection of building materials that are certified green or environmentally friendly to help reduce energy consumption. The aim of this study is to evaluate the energy efficiency of a variety of designs of the building cover best in the glass protector as a building wall material. The research method uses comparative research that involves comparing energy efficiency between 4 different designs and materials with the calculation of OTTV on the facade of the building. Overal Thermal Transfer Value (OTTV) is a design parameter used to measure the level of energy efficiency of a building in reducing the heat from sunlight entering through walls and roofs. The results of the study showed massive walls with a 0.8 m high parapet and 1.2 m sharpening (Aluminum 4 mm with semi-flash white paint + 30 mm airspace + 150 mm precast concrete), along with window walls using the Stopray Vision 52 T (8 mm (#2) +12 mm Anti-Shatter+6 mm Clear Glass) and horizontal shading as high as 0.4 m, as well as openings with a configuration of 8 mm (No2) + 12 mm anti-shatter + 6 mm Clear glass, showing that the Overall Thermal Transfer Value (OTTV) reached its peak with a 29% decrease from the standard value. It states the combination of these elements provides optimal thermal performance, minimizing overall heat transfer.

Comparison of the effectiveness of stabilizing quasi-resonant and inertial influences on the parameters of a controlled Lorentz system with dynamic chaos

Problem statement. The article is devoted to determining the comparative energy efficiency of stabilizing quasi-resonant and inertial effects on the parameters of a controlled discrete-nonlinear Lorentz system with dynamic chaos. Currently, information transmission systems based on the use of chaotic dynamics effects are developing extremely intensively. The need to ensure reproducibility of parameters and statistical characteristics of pseudorandom signals generated on the basis of nonlinear systems with dynamic chaos makes the task of stabilizing chaotic modes of nonlinear devices and systems urgent. Goal. Determination of the comparative energy efficiency of stabilizing quasi-resonant and inertial effects on the parameters of a controlled discrete-nonlinear Lorentz system with dynamic chaos. Results. It is shown that fluctuations causing deviations of the discrete-nonlinear Lorentz system from equilibrium states lead to changes in the quasi-resonant frequency and the effectiveness of inertial stabilizing effects. It is established that the effectiveness of stabilizing inertial effects on parameter b of a controlled discrete-nonlinear Lorentz system increases with an increase in the fluctuation deviation of the system from equilibrium states. The conditions under which stabilizing inertial effects become energetically more advantageous than quasi-stationary effects on the parameters of a discrete-nonlinear system are determined. Practical significance. Ensuring the required regular behavior with the transfer of nonlinear electronic and quantum devices and systems from stochastic to regular mode.

A series electric hybrid wheel loader powertrain with independent electric load-sensing system

Electric hybrid powertrain is a promising way for wheel loader electrification. However, the widely used centralized load-sensing working hydraulic system has low efficiency with imbalance load. A novel electric hydraulic system configuration making good use of the electric drive is needed. An independent electric load-sensing hydraulic system for series hybrid wheel loaders is proposed in this study. The lift/tilt functions are powered by speed-controlled fixed displacement pump and controlled by proportional control valves. The independent electric load-sensing hydraulic system eliminates the system inherent power losses of the multi-actuator hydraulic system and combines the high efficiency of variable speed fixed displacement pump and high dynamic performance of valve control. Simulation study on energy efficiency comparison among the proposed powertrain, the existing hybrid powertrain and the non-hybrid powertrain is carried out to check its potential on fuel saving. Results show that the independent electric load-sensing system improves the working hydraulic system efficiency from 34.0% to 54.9% compared to the centralized load-sensing system. The proposed hybrid powertrain saves 11.8% of the fuel consumption compared to the existing hybrid solution, and 41.9% lower than non-hybrid powertrain.

Empirical Comparison of Energy Efficiency Between 3-Tier and High-Speed 3-Tier Network Topologies

The high levels of energy use for cloud computing affect carbon emissions and climate change. This research thoroughly compares the energy utilisation of conventional and high-speed three-tier data centres (DCs). The green cloud simulator (GCS) was used to compare network configurations and energy-saving algorithms for each cloud's energy consumption in 10 trials. The power saver schedule algorithm used the least server energy, while the green and RR schedule algorithms used more. Despite the testing of several energy conservation approaches, core switch and aggregate switch energy usage remained unchanged. Although the high-speed three-tier DC architecture used more energy than the standard design, this is a key difference between the two network topologies. The authors discuss the power saver schedule algorithm's benefits for server energy utilisation. This study shows how three-tier DC architecture can save money by reducing core switch and aggregation switch energy use. These evaluations should include the make span coefficient, and future research should focus on DC transform energy-saving techniques.

A free piston engine generator powered hybrid wheel loader with independent electric drive

Series hybrid powertrain is a practical way for wheel loader electrification. Conventional internal combustion engine (ICE) technique is mature but the efficiency is limited. Free piston engine generator (FPEG) is regarded as a promising technology that can be applied as decarbonized range extenders attributed to its high thermal efficiency and ultimate fuel flexibility. In this study, a FPEG-based series hybrid powertrain is proposed for wheel loaders to reduce fuel consumption. Multiple FPEG units are parallel connected to power the electric powertrain. The optimal unit commitment of the FPEG set is investigated via dynamic programming. A rule-based strategy called discrete power follower (DPF) is proposed. The influence of FPEG unit number on powertrain performances is studied. Energy efficiency comparison between the FPEG-based and the ICE-based series hybrid powertrains is carried out. Results show that the fuel consumption of the proposed FPEG-based series hybrid powertrain is 10.5 % lower than the ICE-based powertrain. The mean efficiency of wheel loader powertrain improves from 31.7 % to 35.1 %.

Comparative Performance and Energy Efficiency Analysis of JVM Variants and GraalVM in Java Applications

Java has dominated the ICT market for almost thirty years with various applications in nearly every sector all over the world. One of Java's main drawbacks comes from its heavyweight core - the Java Virtual Machine (JVM). Therefore, several JVM distributions have been developed to address this issue. GraalVM is the most promising amongst the recent distributions, providing better performance, low power consumption, and reduced carbon footprint emissions. In this research, a comparative analysis based on performance and energy efficiency metrics was conducted to assess this JVM distribution in light of three other classic JVM distributions: Amazon Corretto, Adopt OpenJDK, and Zulu. Findings showed that, although there was no significant difference between the test candidates, GraalVM seemed to be the leading JVM distribution. It is recommended that programmers and technology businesses consider adopting GraalVM in their future Java applications because of its energy efficiency.

Assessing dynamic energy efficiency in the organization for economic Co-operation and development (OECD) countries and China during COVID-19

According to the October 2021 Glasgow Climate Agreement reaffirming the cooling goals of the Paris Agreement and the Glasgow Leaders Declaration on Forests and Land Use, this research applies the Super-D-DDF model to non-oriented variable returns to scale to evaluate the Organization for Economic Cooperation and Development (OECD) and China (38 countries in total), collect important production and energy variables from 2016 to 2020, and measure the total efficiency of energy dynamics and its changes during COVID-19. The empirical results are as follows. (1) Comparing energy efficiency from 2016 to 2018 and 2019 to 2020 (during COVID-19), we find that most countries (22 countries) changed from high efficiency to low efficiency, showing a decrease in energy efficiency. (2) The emissions of carbon dioxide in China in 2020 are close to the sum of OECD carbon dioxide emissions, highlighting that the energy policy in China should be adjusted appropriately. (3) From 2016 to 2020, the forest area of various countries has a significant impact on overall energy efficiency performance. In line with the United Nations’ policy goals, countries should adjust forest protection policies to effectively reduce carbon emissions.

Импульсные источники ИК-излучения с разрядом в смеси паров щелочных металлов

The paper presents results of research aimed at improving the serial pulsed sources of the IR-radiation based on a discharge in the cesium-mercury-xenon vapor mixture. To create the environmentally friendly gas-discharge source and increase the peak radiation strength, it proposes to replace the mercury buffer in a serial lamp with the rubidium vapor. Based on the thermodynamic analysis, necessity of using cesium as the main component in the plasma-forming medium of IR-radiation pulsed sources was proved. It was established that introduction into the cesium discharge of less than the 25 % (wt.) rubidium provided the required cesium vapor pressure and the plasma thermal conductivity. It was shown that the mass of the alloy with cesium played an important role in the discharge transition from unsaturated to the saturated vapors. Comparison results are presented in peak intensity of the studied IR-radiation gas-discharge lamps depending on amplitude and duration of the supply voltages in the repeated pulsed mode. A technique was developed to compare energy efficiency of the discharges under study, and the spectral research was performed confirming advantages of the IR-radiation pulsed source based on the cesium-rubidium-xenon discharge by the serial gas-discharge lamps

Comparison of Heat-Transfer Energy Efficiency for Direct and Swirl Pipe Flows

Comparison of Heat-Transfer Energy Efficiency for Direct and Swirl Pipe Flows

Detailed experimental comparison of energy efficiency between proportional and direct driven hydraulic system

This paper investigates the energy efficiency of a Direct Driven Hydraulic (DDH) system and a proportional electrohydraulic system. A detailed analysis of their energy efficiency is carried out based on experimental results obtained in laboratory conditions using a fully loaded cylinder and sine wave reference trajectory. To ensure fairness in the testing process, the same cylinder with the same initial conditions is used for both systems. The cylinder velocity is estimated online using a novel algebraic differentiator approach based on measured cylinder position. The power of each component is calculated from the obtained measurements, and the energy efficiency of the system is given, along with the losses for each component. Based on the obtained results, it is concluded that the efficiency of the DDH system with a fully loaded cylinder is 28%, while that of the proportional electrohydraulic system is 4%. The significantly higher energy efficiency of the DDH system is attributed to its use of a power-on-demand approach, in contrast to the proportional electrohydraulic system.

New Approach to Evaluate the Energy Efficiency of Overhead Power Transmission Lines: Results of Theoretical and Experimental Research

This article describes a new approach to evaluating energy efficiency of overhead power transmission lines which is based on power transmission line losses calculation taking into account induction currents and heating in the supporting elements. We present the results of theoretical and experimental research of induction currents and heating evaluation in pylons of the overhead power transmission line. To find the flux linkage for induction currents, calculations using the Poisson equation for vector magnetic potential were carried out. The limiting values of induction currents and heating temperature are estimated using a graphical approach. The analysis of the power losses balance for a 500-kV power transmission line demonstrates considerable energy-saving benefits. The update of the previous conference paper is implying to compare energy efficiency of the overhead power transmission line for thermal and electric energy losses associated with induced currents and to conclude about their interchangeability. Additionally, it is resumed which using technical assumptions in the study. The research work might be of interest for design and modernization of overhead power transmission lines.

Energy Performance Certificate renewal — An analysis of reliability of simple non-domestic buildings ’ EPC ratings and pragmatic improving strategies in the UK

Energy Performance Certificates (EPCs) are designed to provide consistent and comparable energy efficiency ratings. Since 2008, any building constructed, rented or sold is required to obtain an EPC in the UK. 4% of simple office buildings have renewed their EPC to date in England and Wales. In this paper, by comparing the original and renewed EPCs of these buildings, we examine the reliability of non-domestic EPC ratings and discover realistic energy efficiency improvement strategies reflected in the changes. We have found that buildings with their conditions remaining unchanged can be better rated by approximately 10 points on average when their initial rating is above the minimum requirement in the regulation. The ones initially rated below the minimum requirement are expected to have a greater scale of improvement on ratings while making no efforts which brings doubts on the effect of the “Minimum Energy Efficiency Standard” policy. Evidenced human factors are also jeopardising the fairness of EPC ratings. Based on the changes in the EPCs, we have found 4 clusters of improved buildings and 5 clusters of deteriorated buildings. We derived practical energy efficiency improvement strategies that people have already naturally adopted.

Three-dimensional numerical simulation, energy efficiency and economic benefit estimation of oil shale in situ pyrolysis process

Oil shale in situ conversion processing by the downhole burner heating technology (DBHT) has been technically proven as a field pilot project in the Songliao Basin, Northeast China. In this study, the three-dimensional numerical simulations of oil shale in situ pyrolysis with the hexagonal well pattern were conducted based on the idea of DBHT and the actual oil shale reservoir in Songliao Basin to examine the temperature field and thermal processes. The effects of different well spacings (30, 35, 40, and 45 m), gas injection rates (5, 10, 15, and 20 m s−1), and fracture spacings (2.5 and 3.5 m) on the thermal evaluation process were analyzed. The relative energy efficiency and economic viability of operating an oil shale in situ retort in various cases were evaluated. The results showed that increasing well spacing could enlarge the thermal field and improve the ultimate hydrocarbon production of oil shale, but the excessive well spacing caused the heating time to be too long. An increase in the gas injection rate can significantly boost heat transmission efficiency. The energy efficiency comparison of various cases showed that smaller well spacing was conducive to making full use of energy. The results of economic efficiency estimation indicated that a high recovery of shale oil (>80%) would be very difficult to be made with economy, but optimal conditions can be developed in some cases, determined mainly by the price of shale oil. We anticipate that this study can provide new ideas for designing the oil shale in situ conversion processing.

Microwave assisted and conventional hydrothermal treatment of waste seaweed: Comparison of hydrochar properties and energy efficiency

Waste seaweed is a valuable source for converting into value-added carbon materials. In this study, the production of hydrochar from waste seaweed was optimized for hydrothermal carbonization in a microwave process. The produced hydrochar was compared with hydrochar synthesized by the regular process using a conventional heating oven. The results show that hydrochar produced with a holding time of 1 h by microwave heating has similar properties to the hydrochar produced in a conventionally heated oven for 4 h (200 °C and water/biomass ratio 5): carbon mass fraction (52.4 ± 3.9 %), methylene blue adsorption capacity (40.2 ± 0.2 mg g−1) and similar observations on surface functional groups and thermal stability were made between hydrochars produced by both methods. The analysis of energy consumption showed microwave assisted carbonization consume higher energy in compare to conventional oven.The present results suggest that hydrochar made from waste seaweed and using the microwave technique could be an energy-saving technology for producing hydrochar with similar specifications to hydrochar produced by conventional heating methods.

Comparison of Energy Efficiency between Atmospheric Batch Pressure-Retarded Osmosis and Single-Stage Pressure-Retarded Osmosis

Batch pressure-retarded osmosis (PRO) with varied-pressure and multiple-cycle operation using a pressurized variable-volume tank has been proposed as a high-efficiency osmotic energy harvesting technology, but it suffers scalability constraints. In this study, a more scalable batch PRO, namely, atmospheric batch PRO (AB-PRO), was proposed, utilizing an atmospheric tank to receive and store the intermediate diluted draw solution (DS) and a pressure exchanger to recover the pressure energy from the diluted DS before being recycled into the tank. Its performance was further compared with single-stage PRO (SS-PRO) at different flow schemes via analytic models. The results show that the AB-PRO with an infinitesimal per-cycle water recovery (r) approaches the thermodynamic maximum energy production under ideal conditions, outperforming the SS-PRO with lower efficiencies caused by under-pressurization (UP). However, when considering inefficiencies, a ~40% efficiency reduction was observed in AB-PRO owing to UP and entropy generation as the optimal r is no-longer infinitesimal. Nonetheless, AB-PRO is still significantly superior to SS-PRO at low water recoveries (R) and maintains a stable energy efficiency at various R, which is conducive to meeting the fluctuating demand in practice by flexibly adjusting R. Further mitigating pressure losses and deficiencies of energy recovery devices can significantly improve AB-PRO performance.